The Church’s Visible Unity as an Ecumenical Goal

Abstract

The ecumenical movement’s basic purpose is to seek Christian unity. In facing the challenge of mission and ecumenism today, it is important to explicate how the ecumenical movement understands unity currently, and how the concept may have changed. This article’s hypothesis is that the goal of the church’s visible unity has changed less than appearances might suggest. The concept is now generally understood more holistically in ecumenical theology. In this article, a historical-systematic analysis focuses on the concept of visible unity, especially in the unity statements of the Assemblies of the World Council of Churches. An analysis of ecumenical models of unity and ways of realising churches’ unity in practice follows, as well as a reflection on the turns created by the latest ecumenical debate. The analysis confirms that the visible unity remains a central ecumenical goal in the quest for Christian unity. The turn towards holistic ecumenism seems to help address those who shun institutional ecumenism, without forgetting the Trinitarian and Christological theological basis and the institutional dimension. Diversity is not arbitrary: at its best it supports creativity and trust, freeing individuals for common witness and service.

1. Introduction

The ecumenical movement’s purpose is to seek Christian unity. This task is essential to the church’s nature and mission. The current ecumenical movement is thus somehow reliving the situation described in Acts 15 and Galatians 1–2.1 Pope Francis writes: “The world in which we live … demands that the Church strengthen cooperation in all areas of her mission. It is precisely this path of synodality which God expects of the Church of the third millennium” (Pope Francis 2023, p. xii). Jesus prays “that they all may be one” (John 17:21). He links this unity to the core of the church’s mission: “that the world may believe that you sent me”; and to the revelation of God’s love for the world: “I in them and you in me, that they may become completely one, so that the world may know that you have sent me and have loved them as you have loved me” (John 17:23).2 In facing the challenge of mission and ecumenism today, it is important to explicate how the ecumenical movement understands unity in this light, and how the concept may have changed.

The quest for Christian unity is linked to ecclesiology, the church as a communion, and mission. It concerns theology, relationality, and tangible action. This means we need to speak of both “fellowship” and “unity”, underlining that ecumenism is on the one hand about personal fellowship among Christians, and on the other a question of the corporate unity and cooperation of the church and the churches in mission and service. This in turn involves the recognition of the core theological basis: the Christian faith in a Triune God, who is a communion of persons.3 The Trinity embodies unity in diversity. In ecumenical ecclesiology the church can be called the image of the Trinity, in which, according to the ideal, unity in diversity is realised, both within and between churches.4

Ecumenically speaking, every member has a place in the church as the body of Christ, and the boundaries of one church do not reflect the reality of the entire church of Christ. The church’s ecumenical unity is not uniform but has certain elements of identity, classically referred to in the Epistle to the Ephesians: “one Lord, one faith, one baptism” (Ephesians 4:5). The foundation of fellowship is the same for everyone, but everyone is called to join it as themselves. For example, Dietrich Bonhoeffer (1986) emphasises that unity in the Holy Spirit, community, and individuality all belong together in the church.5

Accordingly, unity has both objective and subjective complementary elements. The objective element includes the word, the sacraments as a means of grace, and the underlying Christian tradition: the Bible, the creeds and other confessional foundations, and the common interpretation of doctrine. This also involves the dialectic between the person and the community as an interaction between the individual Christian and the church community. Although there are both organisational and theological differences in the tasks, meaning, and place of the community’s individual members in terms of and as part of the whole, it is evident that all are necessary to manifest the unity of the whole church. No one should be belittled if the image St Paul uses of the church as the body of Christ is applied. New efforts to use the entire community’s resources are characteristic of different denominations. This is certainly visible in Pope Francis’s criticism of clericalism and his emphasis on communal synodality, for example.6

Although community was an important goal, W.A. Visser’t Hooft, the first General Secretary of the World Council of Churches (WCC), felt it necessary to justify why so many church leaders had been invited to the first Life and Work Conference in Stockholm in 1925 by analysing three fundamental ideas that guided the WCC’s founding phase’s planning. First, Visser’t Hooft emphasised: “If the cause of unity was to become a matter for the church, the participation of church leaders was important”. According to general management doctrines, the leadership’s commitment was essential. Second, it was considered important that the churches tangibly express their unity, which simultaneously supported their cooperation. The church’s nature required the expression of the unity of all who believed in Christ. Leadership was an important part of the representational structure. Third, it was emphasised that the basis of the churches’ unity was deeply theological: it was based on the work of Jesus Christ himself. This was also the background for the WCC’s constitutional statement that it was a community of those who “acknowledge the Lord Jesus Christ as God and Saviour”.7

Unity became a stronger focus in the 1950s and 1960s with the WCC’s founding in the aftermath of World War II.8 In the following I examine the formation and refinement of the concept of visible unity in the light of the results of this key ecumenical organisation’s work, based especially on the WCC Constitution, the General Assemblies, and the Faith and Order Commission. What was and what is visible unity as an ecumenical goal in a context where the international ecumenical and political field is fragmented by many developments, while there is also a need for reconciliation, peace, and justice given major common threats like the environmental crisis?

This article’s hypothesis is that the goal of the church’s visible unity has changed less in recent decades than appearances might suggest. The concept is now generally understood more holistically. Realism about the difficulty of achieving the goal has also increased both impatience and indifference. International and national inter-church and societal tensions and major global problems invite us, however, to contribute to building unity to nurture active hope. To undertake this task, I conduct a historical-systematic analysis focusing on the concept of visible unity in the light of the described sources and the ecumenical movement’s development. An analysis of ecumenical models of unity and ways of realising churches’ unity in practice follows, as well as a reflection on the twists and turns created by the latest ecumenical debate in understanding and concretising the pursuit of visible unity.

2. Unity in Amsterdam in 1948, Toronto in 1950, and in the Current WCC Constitution

In Toronto in 1950, the WCC Central Committee began to deepen the discussion of the theme of unity in a situation where new member churches had joined the world organisation, rapprochement between churches had accelerated, and certain critics outside the WCC were accusing it of attempting to be a “super-church” that did not respect churches’ identity and independence (cf. Visser’t Hooft 1982, pp. 70–85).

The starting point was a resolution the Amsterdam Constituent Assembly had adopted in 1948, which in relation to the theme of unity read as follows:

The World Council of Churches is composed of churches which acknowledge Jesus Christ as God and Saviour. They find their unity in Him. They have not to create their unity; it is the gift of God. But they know that it is their duty to make common cause in the search for the expression of that unity in work and in life. The Council desires to serve the churches, which are its constituent members, as an instrument whereby they may bear witness together to their common allegiance to Jesus Christ and co-operate in matters requiring united action. …Unity arises out of the love of God in Jesus Christ, which, binding the constituent churches to Him, binds them to one another. It is the earnest desire of the Council that the churches may be bound closer to Christ and therefore closer to one another.

(World Council of Churches 1948, p. 127)

The statement emphasises unity’s spiritual quality, which is in Jesus Christ. Moreover, unity is a gift from God, not a result of human effort. Yet it is the churches’ duty to seek to express this unity “at work and in life”—that is, in everyday life. The World Council of Churches is not itself this unity or its creator, but the churches’ servant. The WCC does not seek to appropriate member churches’ tasks. It neither wishes to legislate for the churches nor can it administratively do so. The Council seeks a connection between thinking and action between the churches, but it is not itself the unified structure, whose subjects are the churches alone.

The basis of the WCC’s concept of unity is thus neither institutional nor administrative, but theological: God’s love in Jesus Christ. This love binds the member churches to each other by binding them to him. However, this assurance was insufficient, and the meeting of the WCC’s Central Committee in Toronto in 1950 clarified these lines by presenting a series of statements about what the WCC was not:

• The World Council of Churches is not and must never become a super-church.
• The purpose of the World Council of Churches is not to negotiate unions between churches, which can only be done by the churches themselves acting on their own initiative, but to bring the churches into living contact with each other and to promote the study and discussion of the issues of Church unity.
• The World Council cannot and should not be based on any one particular concept of the Church. It does not prejudge the ecclesiological problem.
• Membership in the World Council of Churches does not imply that a church treats its own conception of the Church as merely relative.
• Membership in the World Council does not imply the acceptance of a specific doctrine concerning the nature of Church unity (World Council of Churches 1950).

There were considerable differences in the concept of unity. It was essential for some to achieve full agreement on doctrine, for others sacramental communion based on a common church order, for others both, and for still others unity only on certain fundamental questions of faith and church order. There were also those who emphasised unity as spiritual, making visible unity unimportant or even undesirable. These general conceptions were not characterised as structured ecumenical theory, however. The purpose of ecumenical discussion was seen as to ensure “that all these conceptions enter into dynamic relations with each other” (World Council of Churches 1950).

Among other things, the Toronto statement affirmed: “Nevertheless, membership does not imply that each church must regard the other member churches as churches in the true and full sense of the word” (World Council of Churches 1950). Some Orthodox especially have since emphasised this statement. The 1951 WCC Central Committee meeting in Rolle continued to conduct conceptual revisions, especially of the concept of “ecumenism” itself. It was emphasised that ecumenism, as an aspiration that focused on the essence of the church and its global mission, was seamlessly intertwined with the church’s mission: “…The word [ecumenical], which comes from the Greek word for the whole inhabited earth [oikoumene], is properly used to describe everything that relates to the whole task of the whole church to bring the gospel to the whole world”.9

The discussion has continued over the decades. WCC General Assemblies have always issued unity statements that describe the prevailing view of the promotion of unity, and what the churches are called to do in any given situation, both in their mutual relations and in their mission in and for the world. As the unity statement is adopted by the WCC’s highest decision-making body, the General Assembly, it is ultimately a joint decision of the churches through their representatives, not dictated by the organisation’s officials.10 These statements are not in the strict sense ratified but indicative, yet they can be considered authoritative descriptions of the idea of unity. Binding in a legal sense would require decision-making in each member church and a shared commitment to it.11 According to the established view, the basic model for describing the church’s visible unity as the ecumenical movement’s goal was formulated by the 1961 General Assembly in New Delhi.12

The goal of visible unity is now part of the WCC Constitution. Article 3 states the following about the purposes of the world organisation:

The primary purpose of the fellowship of churches in the World Council of Churches is to call one another to visible unity in one faith and in one Eucharistic fellowship, expressed in worship and common life in Christ, through witness and service to the world, and to advance towards that unity in order that the world may believe.

(World Council of Churches 2022a, Author’s italics)

However, the background of the goal of visible unity requires more detailed investigation, involving a historical-systematic conceptual analysis of both the New Delhi Statement and subsequent developments.

3. The Classic Definition of Visible Unity: The 1961 New Delhi Unity Statement

The concept of the church’s visible unity is based on the distinction the Reformation, and especially John Calvin and Ulrich Zwingli, made between the visible and invisible churches. Influenced by this separation, the early ecumenical movement emphasised the concept of the visible church. It was therefore not merely a question of the weight given by the Orthodox conception of the church to the office of the church and the church as a visible institution, for example. Rather, by opening the connection between the visible and invisible churches, the aim was to emphasise the existing churches’ importance as carriers and mediators of the spiritual tradition and to reject the kind of individualistic spiritualism in which the church as an institution was given no importance. Thus, it would not be a unifying force, either in mission or peace work. As the 1937 Faith and Order conference stated, “…the invisible Church is no ideal Platonic community distinct from the visible Church on earth. The invisible Church and the visible Church are inseparable though their limits are not exactly coterminous” (World Council of Churches 1937).

This is not, however, merely a question of Reformed theology’s terminological influence. The episcopal churches associate the historic episcopate with the goal of visible unity, the culmination of which is ecclesiastical communion. The early church’s ecumenical councils were already synods of bishops that built visible unity. The concept of visible unity today is also related to the desire to implement a genuine sense of community, mutual responsibility, and consideration among churches so that unity has an impact and does not remain merely talk and paper.13

Let us examine the New Delhi Statement on Unity as an expression of visible unity more closely. It starts with the theological premise of unity in the doctrine of the Trinity:

The love of the Father and the Son in the unity of the Holy Spirit is the source and goal of the unity which the Triune God wills for all men and creation. We believe that we share in this unity in the Church of Jesus Christ, who is before all things and in whom all things hold together. In him alone, given by the Father to be Head of the Body, the Church has its true unity. The reality of this unity was manifest at Pentecost in the gift of the Holy Spirit, through whom we know in this present age the first fruits of that perfect union of the Son with his Father, which will be known in its fullness only when all things are consummated by Christ in his glory. The Lord who is bringing all things into full unity at the last is he who constrains us to seek the unity which he wills for his Church on earth here and now.

(World Council of Churches 1961)

Accordingly, the Triune God’s loving will is both the source and goal of unity. Unity as a visible reality in Christ’s church is important, but the horizon of visible unity extends to all people and all creation. This is a consequence of the Trinitarian approach. It is not primarily a human project but God’s work, which will reach its goal only at the end of time. Unity has already been given in the church of Christ. The outpouring of the Holy Spirit opens the understanding that the message reaches beyond geographical and linguistic boundaries. At the end of time Christ will bring our fellowship to fulfilment—to full unity. It is his will that we seek this unity even now. It is part of the Christian faith and the church’s mission.

After this theological basis, the unity statement characterises the visible nature of unity and analyses the premise of unity in the churches’ common faith, basic structures, and life:

We believe that the unity which is both God’s will and his gift to his Church is being made visible as all in each place who are baptized into Jesus Christ and confess him as Lord and Saviour are brought by the Holy Spirit into one fully committed fellowship, holding the one apostolic faith preaching the one Gospel, breaking the one bread, joining in common prayer, and having a corporate life reaching out in witness and service to all and who at the same time are united with the whole Christian fellowship in all places and all ages in such wise that ministry and members are accepted by all, and that all can act and speak together as occasion requires for the tasks to which God calls his people.

(World Council of Churches 1961, Author’s italics)

Unity is both God’s will and his gift. It does not remain invisible and hidden but comes to light. Visibility concerns the entire church in all places. The Holy Spirit leads the church: “all who are baptised into Jesus Christ” and confess themselves as one community by faith in him as Lord and Saviour. The following are distinguished as manifestations and foundations of visible unity: (1) apostolic faith; (2) the preaching of the one gospel; (3) the breaking of the one bread; (4) common prayer; (5) witness to all; (6) service to all; (7) communion with the whole Christian fellowship in all places and ages; (8) mutual recognition of ministry; (9) mutual recognition of membership; (10) that all can act and speak together when God calls his people.

This vision requires, first, an understanding of apostolic faith. The Fourth Faith and Order Conference in Montreal in 1963 already discussed this theme. It examined the relationship between Tradition with a capital “T” and tradition with a small “t”. This refers to the distinction between the gospel of Christ and its manifestation in different Christian traditions. In the 1980s, the research project “Toward a Common Confession of the Apostolic Faith” focused on the apostolic faith and produced the report Confessing the One Faith (1991). It takes the ecumenical explanation of the Nicene-Constantinople Creed (381) in the contemporary context as its premise.

Second, the understanding of the one gospel also presupposes a common understanding of the doctrine of salvation. In the Western tradition this meant and means the doctrine of justification especially. As early as 1963, in Helsinki the Lutheran churches attempted to express Lutheran teaching about the doctrine of justification. No consensus was reached, and the result was the establishment of the Strasbourg Ecumenical Research Institute, which focuses on ecumenical theology.14 It made an important ecumenical-theological contribution to the Lutheran–Roman Catholic Joint Declaration on the Doctrine of Justification, signed on Reformation Day, 31 October 1999. The Methodist, Anglican, and Reformed churches have since adopted it.

Third, there is a need to study the theology of communion and the liturgy of the eucharist, and to explain how the ordained ministry and the concept of the church, as well as the discussion of sacraments versus ordinances, are related to the general understanding of the eucharist. Multilaterally, these themes were compiled by the important convergence documents Baptism, Communion and Office (BEM 1982) and The Church: Towards a Common Vision (2012).15

The question of common prayer also requires discussion because ways of praying differ, and the expression “common prayer” may be understood as a reference to the liturgy as a whole and thus to the eucharist. At the turn of the millennium the WCC’s Special Commission for Orthodox and Other Member Churches also discussed the theme.16

Over the years common witness, its methods, and the discussion of proselytism, for example, have sparked discussion, as well as various forms of diaconal work.17

There has also been discussion of the fellowship with the communion of Christians of all ages in relation to the question of veneration of saints and icons and praying for the dead, as well as what apostolic continuity means.18

The mutual recognition of the priestly office remains an unfinished issue between Protestants and Orthodox/Roman Catholics. The Anglican–Lutheran communion of Porvoo churches has achieved recognition of ordained ministry and membership in the sense that they consider each other’s members their own based on ecumenical agreement and a resulting ecclesiastical fellowship. It is noteworthy that the contemporary discussion regarding “ecumenism of action” was already present in the New Delhi Unity Statement. The “Lund principle” had already been formulated at the third Faith and Order Conference in Lund in 1952, according to which “we should do together everything except what irreconcilable difference of sincere conviction compels us to do separately” (World Council of Churches 1953, p. 170).

4. Unity Models: From Organic to Conciliar Unity

The first Faith and Order Conference in Oxford in 1937 emphasised that the starting point for the quest for unity was already achieved spiritual unity in love for each other and mutual understanding and respect. This was seen as stemming from the church’s theological basis as the body of Christ. It was thus asserted that nothing new was being sought, only to “discover under the guidance of the Holy Spirit the full nature of the Church created by God in Christ”. The goal was to realise “the ideal of the Church as one living body, worshipping and serving God in Christ, as the fulfilment of our Lord’s prayers and of our prayers”. The perspectives of fellowship and unity, as well as spiritual ecumenism and theological ecumenism and the life of the church, are thus intertwined in these premises (World Council of Churches 1937, p. 250).

However, it was also recognised and acknowledged that the quest for the church’s unity had various dimensions. The Assembly distinguished three different perspectives here: (1) Cooperative action; (2) regular and reciprocal intercommunion in the form of the deepest mutual recognition between the two churches, accompanied by the recognition of offices and membership; and (3) corporate or organic unity, which was not thought of as strict uniformity, which no one wanted, but as “the unity of a living organism, with the diversity characteristic of the members of a healthy body”.19

Organic unity was seen as the conception of unity for most of Christianity. It was characterised by the loyalty of all members to the whole church, not just to a part, the free passage from one part of this whole to another as a full member, the sacraments as sacraments of the whole body, and the recognition of offices in the whole body. God’s spiritual gifts would all be preserved in this whole. “The visible unity of the Body of Christ can issue only from the Living God through the work of the life-giving Spirit”. Even if there were no strict uniformity, there should be a joint conference or council as a sign of a certain organisational fellowship promoting effective action to avoid everyone just doing their own thing (World Council of Churches 1937, pp. 252–53).

The report also stated that essential unity in faith or confession was a prerequisite for communion or organic unity. The conference provided a model of what this essential unity of faith might be like in the opinion of most of the churches present:

We accept as the supreme standard of the faith the revelation of God contained in the Holy Scriptures of the Old and New Testaments and summed up in Jesus Christ.

We acknowledge the Apostles’ Creed and the Creed commonly called the Nicene, as witnessing to and safeguarding that faith, which is continuously verified in the spiritual experience of the Church and its members—remembering that these documents are sacred symbols and witnesses of the Christian faith rather than legalistic standards.

We further affirm that the guidance of God’s Holy Spirit did not cease with the closing of the canon of the Scripture, or with the formulation of the creeds cited, but that there has been in the Church through the centuries, and still is, a divinely sustained consciousness of the presence of the living Christ. (Note: known in the Orthodox Church as the Holy Tradition.)

Finally, we are persuaded, in the classical words of one of the non-confessional communions, that ‘God has yet more light to break forth from His Holy Word’ for a humble and waiting Church. We Christians of this present age should therefore seek the continued guidance of the Spirit of the living God, as we confront our troubled time.

(World Council of Churches 1937, pp. 253–54)

Organic unity was in any case seen in the 1937 Edinburgh Faith and Order Conference’s concept of unity as the deepest degree of unity—and thus as a goal. It can be classified as a model of organic unity, the best expression of which is considered the 1961 New Delhi Unity Statement, which speaks of “the unity of all in each place”.20 Meanwhile, the 1975 WCC Nairobi General Assembly’s Unity Statement has been seen as representing another model of unity—that is, conciliar unity (see Saarinen 1994, pp. 115–16).

The Nairobi General Assembly’s Statement on Unity underlines the Trinitarian basis of the understanding of the goal of the church’s unity as unity in diversity. Concerning the conciliar unity based on the “Concepts of Union and Models of Union” consultation document formulated in Salamanca (1973), it states:

The one Church is to be envisioned as a conciliar fellowship of local churches which are themselves truly united. In this conciliar fellowship, each local church possesses, in communion with the others, the fullness of catholicity, witnesses to the same apostolic faith, and therefore recognizes the others as belonging to the same Church of Christ and guided by the same Spirit. As the New Delhi Assembly pointed out, they are bound together because they have received the same baptism and share in the same Eucharist; they recognize each other’s members and ministries. They are one in their common commitment to confess the gospel of Christ by proclamation and service to the world. To this end, each church aims at maintaining sustained and sustaining relationships with her sister churches, expressed in conciliar gatherings whenever required for the fulfilment of their common calling.

(World Council of Churches 1975, p. 60)

The Faith and Order report What Unity Requires (1976) sees the early church’s ecumenical councils as a model for the idea of conciliarity. These had already been examined in the Councils and the Ecumenical Movement (1968) report and at the WCC General Assembly in Uppsala in 1968, which emphasised unity’s global and conciliar dimension as part of the church’s catholic nature.21 In the background were theological endeavour and an attempt to relate the impulses given by the councils of the early church, the Second Vatican Council, and modern requirements such as the stronger involvement of the churches of the South.

On closer inspection, however, the conciliar unity model did not represent a significant change from the previous organic unity model. As we have already noted, the organic unity model did not aim to represent any strict uniformity. Yet some kind of conference or council was needed as an arena for encounters to build and maintain unity between churches. Now, more tangible than before, the wish was to express what organic unity between churches meant, and how it could be realised. The conciliar unity model therefore did not abolish but complemented the organic unity model. It was realistic in placing greater emphasis on the actual differences between churches and various operating environments.22 The outline of the unity model was also related to the WCC’s new constitution adopted in 1975, which set the promotion of visible unity as a central goal of the world organization (World Council of Churches 1976, p. 30).

The What Unity Requires report linked the idea of conciliarity to the shared need to find solutions in a common situation the churches identified. They should develop ways of mutual exchange, communication, and consultation so that they can show each other solidarity and recognise when they could and should speak with one voice. Churches needed support but also criticism and correction—even words of warning—in the situations in which they lived. Gathering in a joint synod required the churches to recognise each other as churches and to celebrate worship and share holy communion. The principle of fair representation was also structural to avoid anyone being left without a voice. Churches could help identify conflict situations in general and take a stand on them. According to the report, this could also help create a stronger understanding of the ecclesiological significance of the ecumenical movement and the World Council of Churches (World Council of Churches 1976, pp. 7–9).

5. Associations of Churches and Declarations of Ecclesiastical Communion

Although organic and conciliar unity are close, their emphases are so different that we can speak of two different ecumenical models. In a sense, both patterns can be identified in terms of how unity has been restored, or how unity has been nurtured within churches in a conciliar or synodal way.

The restoration of unity between the Roman Catholic and Maronite Churches is one example of achieved ecumenical unity. In the case of the Maronites, integration into the Roman Catholic Church was conducted effectively. The background was the joining of forces as early as the twelfth century of a group named after the monastery of St Maro with the Crusaders. Patriarch Jeremiah II of the Maronite Church participated in the Fourth Lateran Council in 1215, and Pope Innocent III confirmed his office the following year. Contacts with the Holy See have worked ever since (Nichols 2010, p. 327; Oeldemann 2024, p. 3).

Not all unions have been implemented equally well. Thus, for example, many Greek Orthodox do not accept Byzantine (Roman) Catholicism. In Bulgaria, Catholics who followed the Orthodox Slavic-language rite were more successful, mainly because of the politically favourable situation. The background was the Bulgarian attempt to strengthen contact with Rome even before the unification council of Florence in the fifteenth century as the Byzantine emperor, Basil II, sought to unite Bulgaria more closely with his empire from 1019 (Nichols 2010, p. 331). Similar mergers also occurred elsewhere in Eastern Europe. The Greek Catholic Church in Russia, Ukraine, and Poland presents a difficult chapter of its own, and it has occasionally provoked strong anti-Western reaction. The dispute over the Melkites in the eighteenth century already cooled Catholic–Orthodox relations significantly. The term “Melkite” is used to refer to Orthodox or Catholics who have adopted the Council of Chalcedon’s Christological decisions, and who belong to the Patriarchate of Alexandria, Antioch, or Jerusalem. In practice, however, “Melkite” refers to Arabic-speaking (Roman) Catholics. The reason for the cooling of relations in the eighteenth century was the installation of rival patriarchs, Orthodox and Roman Catholic, in Antioch (Nichols 2010, pp. 338–47).

Some mergers have led to new demergers, for colonial reasons—in Ethiopia and India, for example. Unification efforts were also partly the result of the exclusivist Catholic ecclesiastical thinking that developed in Europe after the Reformation (Oeldemann 2024, p. 3).

Numerous mergers have also taken place on the Protestant side since the nineteenth century—for example, in Germany when the Lutheran and Reformed churches were united. In the twentieth century the ecumenical movement saw the emergence of several united or uniting churches, exemplified by the Church of South India in 1947. In accordance with the spirit of the time, these churches preferred the “organic unity” model—all in the same place together. The Faith and Order Commission has regularly monitored the development of the united and uniting churches. The most recent example is the Swedish Uniting Church (equmeniakyrkan.se, accessed on 30 May 2025), which saw the Mission Covenant Church, Baptists, and Methodists becoming one uniting church about ten years ago.23

On the Anglican and Protestant sides. the primary method of uniting has been the declaration of ecclesiastical communion, with the Bonn Declaration between Anglicans and Old Catholics in 1931 and the most recent declaration between Old Catholics and the Church of Sweden in 2016. These have all been declarations, though there have been considerable differences in the required mutual recognition of ordained ministry between the Leuenberg Agreement and the Porvoo Declaration concerning sacramental theology and the episcopal office.24 Differences in the interpretation of “unity in reconciled diversity” are related to this.25 Recently, the need for joint decision-making structures has been discussed in these contexts, so the need for conciliar unity seems to be growing stronger.

The Lutheran contribution to the debate is a model called “unity in reconciled diversity”. In the 1970s and 1980s, Professor Harding Mayer developed this as an ecumenical model suitable for the Lutheran tradition at the Strasbourg Ecumenical Institute that considered the importance of denominational traditions in the pursuit of visible unity. The 1977 General Assembly of the Lutheran World Federation in Dar es Salaam considered the model of conciliar unity flawed in the sense that it took insufficient account of the traditions of the confessions themselves. However, unity in reconciled diversity was not seen as a competing model for the model of conciliar unity, as both sought “unity in diversity”. Unity in reconciled diversity can therefore be seen as a Lutheran contribution to the realisation of conciliar unity so that Lutheran churches and others can promote conciliar unity more easily (see Saarinen 1994, pp. 116–17; Karttunen 2017, pp. 13–15).

As a method, hermeneutical approach, or sub-goal, the model of unity in diversity includes the quest for a differentiated consensus—that is, a consensus that reconciles differences concerning questions of content. In this case, whether the matter can be expressed through a common wording is considered so that denominational differences can be allowed in the light of this common basis without overturning the consensus on the matter itself. The best example thus far of this method’s application is probably the Lutheran–Catholic Joint Declaration on the Doctrine of Justification (1999). This is not a question of any “unity in irreconcilable difference”, as has sometimes been said about the model of “reconciled diversity”, but of recording and demonstrating common ground so that the doctrinal judgments of the sixteenth century can be considered inappropriate in the light of consensus.26 The reconciliation achieved has since been strengthened and expanded to various confessional traditions, though dissenting voices remain.

A parallel development that seeks to express a “differentiated consensus” can also be considered an attempt to express not only consensus—that is, consensus and differences—but also where doctrinal “convergence” can be identified. A key example of such convergence is Baptism, Eucharist and Ministry (BEM 1982), which seeks to express the convergence previously achieved in doctrinally divisive issues and outlines the path for further rapprochement and the ultimate expression of fellowship and unity. Examples of the ecumenical projects BEM promotes include mutual recognition of baptism, rapprochement in eucharistic theology and liturgy, and increased consensus on the office of bishop and deacon, as well as the opening of the priesthood to women.27

The BEM process made it clear, however, that increased consensus concerning the framework in which baptism, communion, and ministry were carried out, or the ecclesiological question, was also necessary.28 Likewise, the conciliar unity model needed stronger ecclesiological anchoring. Ecumenical work for the promotion of doctrinal unity therefore continued after the Confessing the One Faith project (1991), which aimed for the ecclesiological recognition of the common apostolic faith and resulted in the creation of the second convergence document, The Church: Towards a Common Vision (2012).

6. The Possibilities of Communion Ecclesiology

The WCC’s 1991 Canberra meeting had already adopted koinonia,29 or communion ecclesiology, as a clear ecclesiological reference point. This was parallel to the publication of Confessing the One Faith:

The unity of the Church to which we are called is a koinonia given and expressed in the common confession of the apostolic faith; a common sacramental life entered by the one baptism and celebrated together in one eucharistic fellowship; a common life in which members and ministries are mutually recognized and reconciled; and a common mission witnessing to all people to the gospel of God’s grace and serving the whole of creation. The goal of the search for full communion is realized when all the churches are able to recognize in one another the one, holy, catholic and apostolic church in its fullness.30

The documents of the Second Vatican Council of 1962–65 and the Catholic–Anglican dialogue report The Church as Communion (ARCIC II 1990) have directly inspired the outline of communion ecclesiology in theology in recent decades (The Church as Communion 1990).31 No less important, however, has been the eucharistic ecclesiology outlined by Orthodox theology and the general increase in interest in New Testament and patristic theology. This was especially the case in the most influential twentieth-century Catholic theological movement, the ressourcement, nouvelle théologie, or back to the sources movement, whose key representatives (Congar, Lubac, Rahner, Semmelroth) participated in shaping the Second Vatican Council documents’ ecclesiology. The reception of the Council’s ecclesiological ideas and the general discussion of ecumenical ecclesiology resulted in the Extraordinary Synod of Bishops of 1985 stating that communion ecclesiology was the central and fundamental idea of the Council documents. The idea of communion is therefore also the central basis of the Council’s conception of unity. Such back-to-back thinking is reminiscent of the Orthodox neo-patristic trend and the related eucharistic ecclesiology models, or the influence of the liturgical movement in the Anglican and Protestant worlds, as well as postliberal theology, which emphasises the historical and social, or communal, transmission of knowledge.32

The Canberra Statement on Unity links unity in the communion of the church to unity in the apostolic faith and the common sacramental life. It emphasises baptism, the recognition of unity, and holy communion as the second (main) sacrament. Unity also includes the mutual recognition of church membership and offices. It includes a common mission in which the proclamation of the gospel of God’s grace and the service of all creation, or faith and love, belong together. The unity statement, in accordance with the classical attributes of the Nicene-Constantinopolitan Creed, culminates in the recognition of the one, holy, catholic, and apostolic church, so that all churches can see this in each other.

In the aftermath of the BEM process, the statement specifies the significance of the sacraments in the vision of unity, the recognition of one baptism, and the ecclesiological connection with the common ecumenical creed of the early church, the Nicene Creed, in accordance with the Faith and Order project “Towards an ecumenical confession of the apostolic faith”. The description of mission and our responsibility for and service of creation has also been sharpened: human beings, created as they are in God’s image, are part of creation, and the conditions for life are shared. The task of cultivation and protection is underlined according to context. Based on this, an ecclesiological project was launched at the Fifth Conference of Faith and Order in Santiago de Compostela, the results of which were published in 2012 in The Church: Towards a Common Vision. Statements were requested from churches, national councils of churches, ecumenical education providers, and private individuals. Communion ecclesiology was the document’s central foundation.

As a result of these processes, the ecumenical movement has established a model of ecclesial thinking in recent decades which understands the church as a communion based on New Testament and early church thinking (Lat. communio). The local church as a community is central, not only as an institution but as fellowship through faith in the Triune God and thus unity among Christians. However, such thinking is not narrowly church-centred but includes a connection with creation and the church’s mission in the midst of humanity and all creation. Its theological basis is the idea of the church as a communion and fellowship between persons in love, the basis and model of which are the interpenetrating or perichoretic unity of the persons of the Holy Trinity. The faith the word and sacraments awaken bestows participation in the life of the Triune God in love.33

7. Feedback on The Church: Towards a Common Vision Document and the “Ecumenism of the Heart”

The Faith and Order document What Are the Churches Saying about the Church? (2021) states that visible unity has been at the heart of the World Council of Churches’ ecumenical vision since its foundation in 1948 (World Council of Churches 2021). It also refers to the first Faith and Order Conference in 1927 (World Council of Churches 1927). For the churches and partners of the World Council of Churches, visible unity is “the ultimate goal of the ecumenical movement”. At each General Assembly there is a confirmed statement of “unity, which is the gift of God and our calling”. Based on the churches’ feedback, it is concluded that ‘…almost all the churches remain convinced that unity is to be understood as the gift of God, that the unity for which we pray and search has to be visible unity, and that such unity demands mutual recognition of one another as belonging to the “one, holy, catholic, and apostolic Church”’.34

However, as the word “almost” suggests, there are certain reservations. Since the BEM document (1982) there have been changes in some churches’ understanding of visibility. They may see communion (koinonia) as better than visible unity to describe God’s gift and our search. In this case a more relational and dynamic way of seeking unity is considered that is more open to diversity in unity than before. There is less interest in institutional models of unity. “But there remains a strong commitment to the unity for which we pray to be visible, tangible, and vivid enough to shape the life of the world”.35

Visible unity still includes the following elements: (1) unity in faith; (2) unity in sacramental life; (3) unity in service, including ministry and mission. These remain key objectives. However, it seems necessary to think more carefully about what this means in tangible terms. Some are frustrated with the quest for institutional/organic unity and want to think about unity in a new way. For example, in questions of authority and office advancing towards visible unity has proved quite difficult. One should find a way to envision visible oneness in a way that inspires, energises, and is exciting—a stronger experiential dimension. Unity should then give a strong witness to the world of Christian love. This would include working together for peace and justice. It should be a faithful response to Christ’s prayer “that they all may be one”. However, there is also a reaffirmation of mission’s proclamatory dimension as an ecumenical goal: “Many of the responses reveal how profoundly the imperative of mission has really become a key priority in the life of many of the churches, both in the sense of service to the world with the transforming of injustice, and in the sense of proclaiming the gospel for evangelism”.36

The Unity Statement of the Karlsruhe 2022 General Assembly considered these results. The statement concerns the general ecumenical development which, in addition to traditional theological dialogues and ecumenical social ethics, increasingly emphasises spiritual and pastoral ecumenism, the connection between mission and unity, and ecumenical action and mutual learning. The aim is to adopt a more holistic approach not only in theology and missiology but in ecumenism. The General Assembly’s theme embodies this while guiding the unity statement: “Christ’s Love Moves the World to Reconciliation and Unity” (World Council of Churches 2022b).

The Karlsruhe Unity Statement emphasises the “ecumenism of the heart”, the counterpart of the “ecumenism of truth”. This emphasis is part of a pastoral approach that presents the message of hope and emphasises holistic ecumenism in a situation where the vision and significance of the church’s visible unity seem to have become blurred. For the first time in the history of unity statements the “ecumenism of the heart” is firmly linked to the theology of love: “… the quest for a true unity is always founded in love: the love of God revealed in Christ and lived in the Holy Spirit, a love that moves us, and moves the world, to reconciliation and unity” (para 14). The call to unity remains urgent and compelling. The goal is “a visible fellowship, one in holy unity”. The emphasis on “holiness” obviously refers to the foundation of unity in the action of the Holy Spirit and in the Trinity, not brought about by imperfect human beings. The statement emphasises that it is essential to find new strength and renewal in Christ’s love to act ecumenically in a holistic way, without underestimating any area of ecumenical work. Articles 17 and 18 of the unity statement summarise the horizon of this reorientation as follows:

17. Can we open our hearts so that Christ’s love may move us in ways that breathe new life into the search for full visible communion? And is this note of love, heard for the first time in this way at an assembly, one that will sound clearly also in the world?

18. The work of unity needs to be inspired anew by the love we have seen in Jesus Christ.

(World Council of Churches 2022b)

The use of the expression “full visible communion” as part of the search for unity clearly emphasises the relationality, concreteness, and dimension of experience connected with the goal of visible unity, replacing “visible unity” with “full visible communion”. It also reveals the relatively widespread practice of replacing “visible unity” with “communion” in the communion-ecclesiological framework. Unity is a path of faith and love, to which the followers of Christ are called, and in which he himself is present. This can be expressed as a summary of the unity statement:

Together in Christ, formed in Christ’s image, walking the way of love, and in repentance, we celebrate unity as both gift and virtue, knowing that we are called to bear witness to communion in a world that too often creates and exacerbates division. In a world of separation, inequality and injustice, Christ calls his followers to witness to the unifying power of the love that is a gift of the Spirit.

(World Council of Churches 2022b, para. 23)

8. Conclusions: The Visible Unity of the Church as the Goal of Ecumenism—Part of the Holistic Nature of Mission

An analysis of the developments has shown that the church’s visible unity remains a central ecumenical goal in the quest for Christian unity. This is seen to accord with the high priestly prayer of Jesus (John 17:21). The turn towards holistic ecumenism seems to help address those who shun institutional ecumenism. From the perspective of denominations that are institutionally critical and emphasise individual experience, especially in the West, and correspondingly from the perspective of congregational thinking, the shift in understanding the church’s visible unity through emphasising the experiential and functional fellowship between people opens new opportunities to formulate the goal of visible unity in a touching and even inspiring way, without forgetting the Trinitarian and Christological theological basis and the institutional dimension.

Rethinking thus also requires a consideration of intellectual and institutional dimensions. The holistic way also considers the elements that support a certain continuity, the reliable operation of the organisation, and the ritual or pedagogical repetition that is key to the transmission of tradition. The cultivation of constructive diversity—the belief in a Triune God as an interaction between persons in love—is one of Christian theology’s basic premises. Diversity is not arbitrary; at its best it supports creativity and trust, freeing individuals for common witness and service.

From this perspective we can certainly find much common ground for joint action and reflection between various Christian traditions on unity: fellowship on the one hand; unity on the other. What does it mean that the love of Christ calls and even forces Christians to build unity, realising that in the light of Christian faith perfect unity will only be realised at the end of time, when the kingdom of God is all in all?

The Sixth Faith and Order World Conference marking the 1700th anniversary of the Council of Nicaea in 325 will convene at the St Bishoy Monastery at Wadi El Natrun, near Alexandria in Egypt from 24 to 28 October 2025, to consider the theme “Where now for visible unity?”. This will be approached from the interconnected perspectives of faith, mission, and unity. A holistic perspective is indicated when searching ecumenically for hope for the world in the light of Christian faith. Creation and redemption belong together: “A world of climate catastrophe, pandemic, war, and economic concern requires a fresh engagement of the churches with one another on the core issues of faith, unity, and mission that both unite and continue to divide them” (World Council of Churches 2025).