The Virtue of Religio in Thomas Aquinas: Between Justice and Love

Abstract

The aim of this article is to interpret the virtue of religio in the thinking of Thomas Aquinas against the background of his Summa Theologiae. In Summa Theologiae, the issue is placed in the context of justice and injustice; thus, this article seeks to show the deeper reason as well as the possible connections between religio and iustitia. Justice, according to Thomas, is preferably realised where there are differences among people and some debt (debitum) occurs that needs to be settled. The inclusion of the virtue of religio under justice is justified by the existence of a relationship in which a debitum also arises, but settlement is impossible. Aristotle, who inspired Thomas, claims that true friendship rests on similarity and equality. This article wants to present how this opinion of Aristotle could be manifested in Thomas’s description of the virtue of religio. The article posits the question of whether the gift of friendship with God does not permit us to give a new interpretation of the virtue of religio. The authors conclude that, together with love, the virtue of religio is infused into man, thanks to which he can perform deeds commensurate with the goal of ultimate beatitude. For a person who loves God, the act of religio is not only a means of satisfying the demand of justice towards the Creator of all things but also a grace in which he returns his love to God.

1. Introduction—Defining the Basic Platform

Before we embark on a more detailed explanation of Thomas’s concept of religio, we will look at some interpretations that better demonstrate and illuminate Aquinas’s classification in Summa Theologiae.

Here, at the very start, the question arises: why do we want to deal exclusively with the work Summa Theologiae and why not with the work Scriptum super Sententiis or Summa contra Gentiles? The answer is primarily because, in the first-mentioned work, Thomas is bound by the thematic framework of Peter Lombard, who, in his first book, discusses the doctrine of the Triune God; in the second, creation and sin; in the third, Jesus Christ; and in the fourth, the sacraments and final matters.1

Similar reasoning guides us in the case of Thomas’s Summa contra Gentiles. This is not a philosophical work, however, as Alois Dempf mentions in his introduction to the German edition, it is a theological work with an apologetic character. In many manuscripts, it is mentioned under the title: Liber de veritate catholicae fidei contra errores infidelium2. The basis of this work is the consideration of a two-fold truth about divine matters: one that, on the one hand, can be reached by human reason—and, thus, be made clear to an adversary—and, on the other, a truth that goes beyond human reason and transcends it. In the second case, the truth itself cannot be directly proven, “there are, however, some probable reasons available for the declaration of this truth, to the exercise and consolation of the faithful, but not to the convincing of opponents” (Aquinas 1961, I, 9).

Both of the mentioned works—in our view—are not conceptually or interpretatively constituted such that they discuss the virtue of religio in a philosophical and theological way, but rather look at this topic through the lens of one specifically constructed topic. If we now want to analyse Thomas’s Summa Theologiae, it needs first be emphasised that, unlike other works, it is intended for a student, to whom the whole of a certain field of scholarship is presented in a broader context of its arrangement and in its clearer conceptualisation. The need to systematise, as well as the attempt to “conceptualise” the issue of religio, arises from the “ordo disciplinae” addressed specifically to students and also represents, for the teacher, a record of how he himself has progressed in his thinking as a teacher and professor.

In this sense, we will focus on the issue of the virtue of religio in Thomas in the Summa Theologiae and will approach this topic first from the semantic point of view, as a possible interpretive connection to Aristotle (Section 2.1) or an interpretive connection to Cicero (Section 2.2). We will then focus on the very interpretation of the concept of religio in Thomas (Section 3). We will describe the virtue of religio as a distinct moral virtue connected with the virtue of justice. The question is often asked whether the virtue of religio is somehow also connected with the theological virtues and is sometimes even itself considered a theological virtue (Augustine 1969, 3, 9). We will clarify this issue and discuss the question of mutual articulation and connection of the theological virtues and the moral virtue of religio (Section 4). We will introduce the concept of the infused moral virtue of religio and distinguish it from the acquired moral virtue of religio. Reflecting on Lottin’s elaboration of this topic (Section 4.1), we will ask whether religio is merely a matter of a righteous act of man or also a reciprocation, an expression of friendship, which is always preceded by God’s loving gift (Section 4.2).

2. Basic Semantic Definition and Approximation of the Term Religio

For a correct understanding of the concept of religio3 in Thomas, it is important to take note of the context in which he himself places it. Thomas focuses on the virtue of religio in the Summa Theologiae after first discussing the question of law, justice and injustice. He describes the virtue of religio as a moral virtue that guides a person’s will to deliver to God the respect that belongs to him as the first principle of all beings. According to him, the virtue of religio does not have God as its subject, but its subject is the divine cult. God is more the goal towards which acts of worship inspired by religion are directed, rather than the subject of virtue as such (Aquinas 1889, II-II, 81, 5). Therefore, we must first approach several of Aristotle’s interpretations of the virtue of religio precisely in the context of justice and law and the virtue of religio by the rhetorician Cicero.

2.1. The Virtue of Justice in Aristotle’s Nicomachean Ethics V

The starting point for Thomas in the case of religio is Aristotle’s Nicomachean Ethics and his definition of justice. Aristotle analyses justice in Book V, amidst, so to speak, the practical and theoretical virtues.

For Aristotle, justice is typical in that its aim is not within the person himself, but in relation to someone else (1129b). In the case of theoretical virtues (e.g., prudence or practical virtues (courage, gentleness…), the “aim” of the virtue remains within the person and improves the person’s actions/knowledge. We can, thus, say that it regulates something “between” people, that it does not remain only in the acting person.

He actually divides justice into general and special types (Aristotle 1999, V, 2). In the first, the general sense, it is primarily understood as equality and fairness, which renders the elementary term in more detail. Everything that is in conflict with the law is contrary to the concept of justice. In this sense, every person has the same rights from birth—the opposite would be an injustice, a wrong. Aristoteles says that in justice “all virtue is summed up” (1129b30), that this is the “complete exercise of complete virtue”, and only thanks to this is a person able “to exercise virtue in relation to another” (1129b30–31). In his view, justice is “the only virtue that seems to be another person’s good” (1130a 4–5).

Therefore, Aristotle distinguishes between justice and partial justice (special) (V, 4). He recognises, however, that people are basically born different, not only with different interests, but different abilities and values, and it is specifically because people are different. Therefore, the aim of justice to a certain extent is to “smooth over” these differences. To do this, Aristoteles divides this special justice. One species of it concerns the distribution of the honours of wealth or anything else that can be divided among members of a community in a political system (1130b), and a second species concerns rectification in transactions (1131a).

Merely the fact that a person lives in a community from his or her birth justifies why justice is one of the primary virtues for Aristotle, as it regulates the relationship of father to son, daughter to mother, and citizens to each other (Aristotle 1999, 1134b). Anywhere where two people live, their relationship is governed by it, as it “balances out” the differences between inequalities if something is denied to someone or if something is lost due to the actions of another person. We can assess this loss both materially and spiritually. If I, for example, lose bread, such a loss can surely be replaced with other bread. But will it be equally possible if I were to lose something loftier—that is, some spiritual thing?

Aristotle acknowledges that, in this case, harm can only be replaced with difficulty. It is not easy to settle any inequality and injustice. If honours and merits are involved, the judge obviously tries to consider fairly in what way a given citizen could be “appraised”. But this is otherwise in the case of spiritual loss. If, for instance, I lose my good reputation and good name because someone wrongly accused me of something, we know very well that it is difficult to restore that good name.

He returns to the topic of justice in Book VIII on friendship. He believes that friendship “replaces” and completes what is imperfect in justice. It goes beyond the purely normative level of the deed (from where–to where), and even gives “more” than it must (Heck 1971, p. 37). Aristotle recognises that if people were friends with one another, no justice would be necessary, but where there is justice, friendship is even more necessary (Aristotle 1999, 1155a)—in the circumstances of our changing life with others, this is the most necessary virtue. Aristotle, therefore, distinguishes between perfect and imperfect friendships. Imperfect friendships are based either on utility or pleasure or advantage (1156a). When people change, their interests also change, and such imperfect friendships end because they are based on differences (1157b). Aristotle also considers the friendship between a father and son or a sovereign and subject among such friendships based on differences (1158b).

Perfect friendships, however, according to Aristotle, must be based on equality (1159a). They require stability and the unchanging side of the spirit—virtue. Aristotle comments on this: “Equality and similarity, and above all the similarity of those who are similar in being virtues, is friendship” (1159b5). Virtue is, thus, “above all”, a similarity, which enables stability and friendship even between people of different status, age or origin.

In his work, Aristotle also mentions the gods, saying, at one point, that whatever justice concerns them, it is always certainly unchanging (Aristotle 1999, 1134b28–29). The gods are constant and immutable in their justice and offer the most just judgments. Aristotle then immediately indicates that the gods take part in things that are good in themselves such that they “can have no excess of them” (Aristotle 1999, 1137a28–29). In this, Thomas builds on Aristotle, according to whom, it is virtue (and the virtue of religio) that balances the differences between God and man and enables him to become his friend.

2.2. Cicero and His Understanding of the Virtue of Religio as That Which Is “To Be Obtained or Performed”

For Thomas, Cicero was a direct starting point for thinking about religio as a virtue, in general, and assigning it to the cardinal virtue of justice. Later, this specific interpretation of his appears in Macrobius, Augustine or Isidore of Seville. Cicero defines religio as an “attitude of the spirit” (habitus animi), through which the common good is sustained and which gives each person his or her dignity. Thus, the virtue of religio has its origin in nature, and man follows this nature and improves it with his attitude in what nature expects and requires from him. From this, then, custom is constituted, its observance and, in the end, positive law. Thus, the order is as follows: natural law, customary (unwritten) law, and established positive law. The virtue of religio, thus, emerges directly from natural law, from justice, which represents the original state at the beginning, the original force (vis), and is not the result of the changing opinions of people. According to Cicero, this situation of justice applies, in a similar way, not only to religio but also to respect, gratitude, redress of wrongs and truthfulness. Cicero subsequently offers a definition of religio (Cicero 2010, p. 27)4 as a virtue that performs a certain sacred service and commitment to a higher nature, which he calls divine. From this, it is evident that Cicero does not distinguish between the cardinal virtue of justice and partial virtues (partes). He rather understands it as natural justice, which is further the basis of all other virtues. It then follows that religio is also a part of and a result of justice, as each part is part of a larger whole.

It, thus, follows that religio is also a component of justice, as a part is part of a larger whole. So, is this virtue acquired by person?

Knowing that I should serve the gods and be fair to them has a clear purpose. Cicero uses the term cultus for this “service”. This noun can mean cultivating a field, caring for a friend or friendship with people but also respect or piety towards the gods. It indicates the true interaction between the cultivated and the cultivating, where one always benefits the other. We find a similar interpretation of the virtue of religio a little later in Aurelius Augustine’s De vera religione (Migne 1841, p. 172)5.

The aim of knowing this type of service to the gods is, in Cicero’s view, to correctly understand the human basis of this interaction. Gods and humans cannot affect or bring benefits to one another without religio. Similarly, justice towards the gods has, as its purpose, some obligation; it requires some response from man. But how can a person be “just” towards God? How, when, in Cicero’s view, we are not in direct communion with the gods, that is, we cannot have any obligation towards them (and we cannot communicate with them at all)? This justice towards the gods, it seems, loses its assumed purpose in Cicero.

What, then, does religio mean? One possibility is that Cicero in this case also uses religio as a virtue. We also find this usage in other places in his works. In his youthful work, De Inventione, he called religio a type of justice, which is not opposed, but is alongside, the vice of superstition (Cicero 2010, p. 27). He states that superstition resembles religio much like rashness (a vice) resembles courage (a virtue) or severity (another vice) imitates justice (another virtue) (Cicero 2010, p. 81; Wynne 2019, pp. 62–63). Therefore, the question of the virtue of religio is complicated in Cicero, but it is clear that it is placed in the context of justice.

3. Religio in the Context of Justice according to Thomas

According to Aquinas, justice takes into account a “relation to another” (Aquinas 1889, II-II, 57); it has the good of another person in mind. On the one hand, it shows the difference between “I” and “You”; it shows that there are different positions and expectations between them. On the other hand, justice also emphasises the difference between “mine” (I have the right to this and that) and “yours” (this is your right). This is equally true in the case of duty—justice determines what duty results for me at a given moment and what for the other person.

What mainly determines this “relationship” is the fact that the other is a different person. My existence and his existence, my expectations and his expectations are not completely identical. His and my ontological starting points are different, and therefore, what can be “established” with justice, according to Thomas, are rather things that apply to external, common life. This is why justice is carried out primarily “in external proceedings” (per exteriores actus). In such a case, even a third, disinterested person is capable of judging whether something was done fairly or not, sufficiently or not, or whether we gave something to someone rightly or not.

But like Aristotle, Thomas differentiates between the legal and moral levels of justice. While the former can be “checked” externally, the latter falls into the area of a “non-normative” relationship to the other. Among the relationships in which it is not possible to establish equality legally are the relationships to parents, to fellow citizens and to one’s homeland (pietas), to superiors (observantia), to benefactors (gratitudo) and friends (amicitia), and Thomas extends moral justice not only to the topic of “two people”, but also to “what belongs to God” (religio) (Pieper 1966, p. 10).

The relationship towards God, according to Thomas, is not just one of the relationships that a person must take into account. God is, namely, the supreme benefactor (summus benefactor) for man (Aquinas 1889, II-II, 107, 2 arg. 1). Everything that exists comes from Him: He is the primum principium of everything (Aquinas 1889, II-II, 81, 1 ad 4). Through His wisdom, will and power of goodness, He creates and arranges everything (Aquinas 1889, II-II, 81, 3 ad 1), and everything leads to Him and finds its completion in Him (Aquinas 1889, I, 6, 1). He created man in His own image to be “the principle of his actions, as having free-will and control of his actions” (Aquinas 2012, I-II, pr.). To speak of justice in relation to God may seem unreasonable given the magnitude of the blessing received. Is it in a person’s power to repay this favour and, thus, restore the balance? How is it possible to return something in equal measure to someone from whom a person has everything? The relationship towards God essentially bears in it something asymmetrical. It is not an equal relationship, as is the case with legal relationships between people, but one of one-sided dependence. What remains to the recipient to return, after receiving the gift as an obligation—the so-called debitum—is disproportionately high, and even if a person were to follow the path of reciprocation and return, in reality, he cannot give God anything that he has not previously received from Him and that he no longer owes Him: “What do you have that you did not receive?” (1 Cor 4:7). “What shall I return to the Lord for all his goodness to me?” (Ps 116:12). Despite good will, we cannot achieve a settlement befitting justice, which, from the definition, gives to each what is his. How, then, can the inclusion of the virtue of religio under justice be understood? How does religio realise the concept (ratio) of justice?

Even if there are unequal relations between God and man, and man is unable to repay God for his gift, this cannot be, in Thomas’s view, an excuse for not being obligated to repay. Something similar also applies to the other relationships we named above. Even in relation to our parents, our ancestors or our teachers, our debt cannot be nullified. Since the virtues of religio, pietas, observantia, gratitudo and amicitia do not realise the whole concept of justice as equality, Thomas considers them only as potential (not integral) parts of justice. But although we cannot fully realise the concept of justice in these relationships according to equality, we still have the opportunity to do it as we are able (Aquinas 1889, II-II, 80, 1). “When it is impossible to repay the equivalent, it suffices to repay what one can (quod possibile est)” (Aquinas 2012, II-II, 62, 2 ad 1). We cannot give or return “something” to God and live our life as if we have paid off our debitum. What we can and have goes deeper, to the core, where our basic approach to ourselves is decided: whether we will become confessors of God’s greatness in the will, who have admitted our subordination, or whether we will serve false gods. Therefore, religio is a virtue of our will; it is the will “to give due honour to God (exhibere Deo debitum honorem)” (Aquinas 2012, II-II, 81, 4). It is an expression of our freedom, because man may not recognise God’s supremacy, but this is obligatory because divine majesty and goodness demand recognition of what belongs to God (ius suum). At the same time, we can say about religio that it is “more a matter of the heart eager to repay than the deed of repaying” (Kaczor 2022, p. 2). Its fundamental act is inner devotion (devotio), which Thomas defines as “the will to give oneself readily to things concerning the service of God” (Aquinas 2012, II-II, 82, 1) or also as “an act of the will whereby a man offers himself for the service of God Who is the last end” (Aquinas 2012, II-II, 82, 1 ad 1). Thanks to the inner resolution to serve God, the overall perspective of how one sees oneself changes because a person offers God his interior, his heart, himself, not just something from his life, some reserved moment or religious act. “As the gift is total, encompassing both the ‘unfailing principle’ and ‘ultimate end’ of our existence, so too is the honour and service it requires unlimited and absolute, taking in every aspect of our lives” (Case 2021, p. 329). “[…] justice tends to make man repay God as much as he can, by subjecting his mind to Him entirely” (Aquinas 2012, II-II, 57, 1 ad 3).

Thomas does not link knowledge of God, which is a prerequisite for the moral virtue of religio, with any special grace or any special revelation, but with the good use of what makes each person human—with reason and the desire to know the truth.6 In his view, each person can realise that he should pay tribute to the Creator of everything (Rom 1:20; Levering 2014, p. 190; Kaczor and Sherman 2008, p. 63). Nevertheless, “his knowledge of the Divine is limited to what can be worked out by natural reason (and it may not even get that far)” (Budziszewski 2017, p. 245). Man comes to know God vaguely with his reason, as the One Who is and to Whom respect is due. He does not know His essence; he only infers its existence from the traces of His presence in the world.

This leads us to the question of whether something changes in the nature of the virtue of religio if a person opens himself to God’s revelation. In other words, after an act of conversion, does religio remain an acquired virtue attached to justice or does it take the form of love and, thus, become an infused virtue?

For developing this question, we will first approach how theological virtues operate within a person and how they transform his or her vision of the world, God and the self. We will elucidate why the concept of debitum can seem insufficient to a religious person to express his or her bond with God. We will then return to the question of how Thomas understood the relationship between theological virtues and the moral virtue of religio. We will answer this in two steps: First, we consider Odon Lottin’s interpretation of this relationship. Second, we will offer our own interpretation of this relationship.

4. Religio against the Background of the Friendly Relationship between God and Man

Faith is in the understanding of Thomas and Christian tradition, a gift from God, which offers a person participation in God’s own life. It is participation through community, closeness and friendship. “I no longer call you servants […]. I have called you friends, […]” (John 15, p. 15). The message of the Christian faith tells of the possibility of friendship between God and man: “A faithful Christian has become a child of God, has fellowship with God, has become an heir of God, (…) no longer a servant, but a ‘friend of God’” (Schmidbaur 2009, p. 211). With the gift of faith, man dwells in the closeness of God, in the community of love, in the intimacy of sharing goods (Aquinas 1889, II-II, 23, 1) and is enabled to perform deeds commensurate with the supernatural goal of life (Aquinas 1889, I-II, 61, 1). Compared with acquired virtues, which direct a person to natural goodness, i.e., to life, according to reason in communion with others, the infused virtues of faith, hope and love relate to achieving a supernatural good, a life with God. Acquired and theological virtues are, thus, necessary with regard to other goals. What is being disputed here is the mutual articulation and connection of these two types of virtues.

In the case of the articulation of the virtue of religio and the theological virtues, two difficulties may arise. The first is caused by the legalistic notion of religio. If we place a debt (debitum) and its repayment at the centre of the virtue of religio, then the danger arises that our relation to God will turn into self-justification and legalism (Heck 1971, p. 51), which would contradict the undeservedness of the gift of friendship with God.7 We will respond to this difficulty only briefly because it is a significant departure from Thomas. As we have seen, Thomas assigned the virtue of religio to moral justice, which is not based on the legal settlement of the debt but on giving back and returning according to human possibilities.

The second difficulty is more subtle. Thomas holds the view that God gives a person, together with faith, hope and love, the seeds of the so-called infused moral virtues, because the soul needs to be perfected not only for dwelling with God in the unity of love, but also “in regard to other things, yet in relation to God” (Aquinas 2012, I-II, 63, 3 ad 2). This would mean that alongside the acquired moral virtue of religio, an infused moral virtue of religio also exists in the believer. This could be the answer to the question of the connection between the moral virtue of religio and theological virtues. It only remains to clarify how Thomas understands the infused moral virtue of religio.

4.1. The Infused and Acquired Virtue of Religio according to O. Lottin

Dom Lottin sees the difference between acquired and infused religio only in their origin, not in their essence: both, namely, dispose a person in the religious field to performing actions consistent with common sense (Lottin 1920, p. 11). He notes that infused religio still remains a moral virtue. A religious person does not honour God because this is his highest good, nor because he believed in his revelation. These motives, in Lottin’s view, are subjective. They may contribute to greater resolution on the part of a person or to the merit of an act infused with religio, but they cannot change the intrinsic reason (le motif) of the religious act, which is the natural obligation to give to everyone what is due to him (Lottin 1920, p. 18).8 The task of religio is not to reach God, but to facilitate acts of his worship such that they are consistent with our nature. Like any other moral virtue, the religio of a believer, too, seeks a “centre” in the area that is its own, and this, says Lottin, is its main mission.9

Lottin’s interpretation of religio in Thomas strictly follows the Aristotelian theory of moral virtue, which says that virtue is the centre in a certain area of action. For the virtue of religio, it is sufficient that a person fulfils his natural obligation (l’obligation naturelle) to give everyone that which belongs to him. It is sufficient that he recognises what he is, that is, his dependence on God, and expresses it through acts of worship (Lottin 1920, p. 18). Lottin sees the only difference between acquired and infused virtue of religio on the side of the intention of the person acting and on the side of merit, but this difference, in his view, changes nothing about the object of the deed.10 However, emphasising the object of a religious act may overshadow what we express most by the given act: our intention to re-ligare, to bind together with God.11 We, thus, run the risk that our religio will become a formal act of duty. We will comment on the role of intention in the act of the virtue of religio in more detail in the next part of this article.

4.2. Reconsidering the Infused Virtue of Religio

Thomas describes the fundamental difference between acquired and infused virtue in connection with the definition of virtue, stating that virtue is “a good quality of the mind, by which we live righteously, of which no one can make bad use, which God works in us, without us” (Aquinas 2012, I-II, 55, 4, arg. 1). The last part of this Augustine-inspired definition—“which God works in us, without us”—relates only to infused virtues. While acquired virtues come from our natural beginnings and through them we achieve natural goals, infused virtues are within us from God’s gift, and they direct us to the supernatural aim of life, which is ultimate and complete beatitude.

The subject of moral virtues (materia propria) is some area of human goodness, and this is the same for acquired and infused moral virtue (Sherwin 2018, p. 174). In the case of the virtue of religio, this area is what a person sacrifices to God in his respect (Aquinas 2005, I, 12 ad 11), that is, the proper acts of worship (debitus cultus), through which we want to glorify God (Aquinas 1889, II-II, 81, 5). Thus, the subject of the moral virtue of religio (acquired and infused) is not God himself, but acts of His glorification, and the measure of our action (the so-called mean), in this matter, is determined by reason. If the measure of natural reason did not differ from the measure of reason perfected by faith in our acts of reverence for God, we could agree with Lottin that in regard to the subject, there is no difference between the acquired and infused moral virtue of religio. Thomas, however, says that human reason and God’s law do not provide the same measure. He presents the virtue temperance as an example: “For instance, in the consumption of food, the mean fixed by human reason is that food should not harm the health of the body nor hinder the use of reason: whereas, according to the Divine rule, it behooves man to ‘chastise his body, and bring it into subjection’ (1 Cor. 9:27), by abstinence in food, drink and the like” (Aquinas 2012, I-II, 63, 4). He concludes from this that “infused and acquired temperance differ in species; and the same applies to the other virtues” (Aquinas 2012, I-II, 63, 4). In its search for the mean, infused moral virtue is guided by the word of God. In reaching God, the ultimate goal and object of the theological virtue of love (caritas), the infused moral virtue relies on resources beyond the power of man (grace). When the infused virtue of prudence considers what act of divine worship is appropriate to God, it relies preferably on what God’s word and the faith of the Church reveal to us about the way of worshipping God. These forms of worship of God (e.g., the sacraments or other acts of religious devotion) are acts of infused religio and means of glorifying the Triune God. Through them, not only does a person respond to the natural debitum towards God and satisfy the demand of justice but they also “strengthen the theological virtues and engender growth in sanctifying grace” (Murray 2018, p. 162).

The relationship between infused religio and love is, thus, a relationship of “means” and a principle. While in acquired religio this is a question of “how properly to relate to God (which always remains a fact of life, of course),” in infused religio, it is a question of “how to commune with God” (Chenu 2002, p. 38). A person becomes more accessible to grace thanks to love. This is driven by a desire for the living God and not just by the duty to redress justice. Thomas considers love to be the mother (mater) of infused moral virtue (Aquinas 1889, II-II, 23, 8 ad 3). Love is simultaneously the source from which religio is sustained and watered, and the ultimate reason for religio acts. “(…) charity both causes devotion (inasmuch as love makes one ready to serve one’s friend) and feeds on devotion. Even so all friendship is safeguarded and increased by the practice and consideration of friendly deeds” (Aquinas 2012, II-II, 82, 2 ad 2).

Thomas uses the word “command” to name actions that express one virtue but are motivated by another virtue (Austin 2017, p. 181). The love of a believer is just such a “commanding virtue”, because it incites a deed of the virtue of religio. The will immediately chooses the act of the virtue of religio, but it is directed not only to its own goal of the virtue of religio but also to the goal of love. The virtue of religio seeks the appropriate worship of God (debitus cultus), but the higher virtue of love seeks the strengthening of friendship, intimate sharing (familiaris conversatio) and reciprocity (redamatio): “mutual indwelling in the love of friendship can be understood in regard to reciprocal love (secundum viam redamationis): inasmuch as friends return love for love, and both desire and do good things for one another” (Aquinas 2012, I-II, 28, 2).

We can, thus, say that Thomas’s concept of infused moral virtue connects the moral virtue of religio and the theological virtue of love such that the primary mission and form of the virtue of religio do not disappear, but its act acquires an added form of love and a new participation in life with God.

5. Conclusions

Thomas developed his interpretation of religio against the background of the works of Aristotle and Cicero, taking from them the inclusion of religio under the virtue justice, which enabled him to describe religion as giving to God what is due to Him (debitum). The thinkers of antiquity were well aware of man’s inability to return to God what is His according to some equality and, thus, the perfect concept of justice, but despite this awareness of the contradiction between the human possibility and the duty of justice, Aristotle did not hesitate to label a life of resemblance to God as that which is most valuable. He stated that returning to God what belongs to Him is more about returning to God than giving something in return. However, his way of philosophical contemplation did not count on the possibility that some kind of reciprocity and equality, which he considered an essential sign of friendship, could exist between man and God (Aristotle 1999, 1157b–1158b).

Compared with ancient thinkers, Thomas was in a different situation, in that in his search for the essence of the virtue of religio he could integrate the revealed word of God, on which the faith of Christians rests. This enabled him to consider the virtue of religio against a background of the possibility of a new relationship between man and God. God offers man friendship, removing distance, and introduces him to his inner life through the gift of love. Infusing love (caritas) into a person’s heart also forms his virtue of religio. Its innermost essence is spiritual communion with God (Aquinas 1889, II-II, 23, 1), intimate sharing. This indwelling of love in man transforms the inner act of the virtue of religio, devotion (devotio). A pious person (devotus) surrenders his will, gifts his inner being to God, who enabled him to do so with the gift of love. His religiosity no longer stands only on the duty (debitum) that results from justice but also on the reciprocation (redamatio) of love to God.