Marriage: The Greatest of Friendship

Screen Shot 2019-03-01 at 4.40.20 PM.png


IN order to understand the nature of the mystery of holy matrimony, we must contemplate the reality of what is actually implied when we speak of the spousal relationship, of what we mean when we speak of marital union, and what sort of relationship a husband and a wife are meant to share. Put briefly, we can say along with Thomas Aquinas that “between husband and wife, it seems, there exists the greatest of friendship” [1]. Aquinas seems to view marriage principally through the lens of friendship, and all that this entails. We will investigate just what this means, what it implies, and the various conclusions we must draw from such a claim.

A. What is Marriage?

Marriage, properly speaking, is a “matrimonial covenant, by which a man and a woman establish between themselves a partnership of the whole of life” (CCC, §1601). Fleshing out this definition, Gaudium et Spes includes a succinct and beautiful description and summary of the reality of marriage:

The intimate partnership of married life and love has been established by the Creator and qualified by His laws, and is rooted in the conjugal covenant of irrevocable personal consent. Hence by that human act whereby spouses mutually bestow and accept each other a relationship arises which by divine will and in the eyes of society too is a lasting one [2].

Here we see the basic structure that we call marriage: a lasting covenant relationship  established by free, mutual consent.

What is more, this covenant relationship is characterized by two distinct, yet related, ends:

By their very nature, the institution of matrimony itself and conjugal love are ordained for the procreation and education of children, and find in them their ultimate crown. Thus a man and a woman, who by their compact of conjugal love “are no longer two, but one flesh” (Matt. 19:6ff), render mutual help and service to each other through an intimate union of their persons and of their actions. Through this union they experience the meaning of their oneness and attain to it with growing perfection day by day. As a mutual gift of two persons, this intimate union and the good of the children impose total fidelity on the spouses and argue for an unbreakable oneness between them [3].

In essence, Gaudium et Spes is merely echoing the age-old teaching of the Church that marriage is ordered primarily to the procreation and education of children, and secondarily to the mutual help of the spouses [4].

Though the vocabulary is different, and more elaborative, what Gaudium et Spes describes is the outworking of the teaching which Aquinas offered seven centuries prior (and which someone like Augustine offered eight centuries prior even to Aquinas). Though absent from his treatise on the sacraments in the Tertia Pars of the Summa Theologiae—an unfortunate accident occasioned by St. Thomas’ untimely death—he speaks eloquently of marriage in his other masterwork, the Summa Contra Gentiles:

Now between husband and wife, there would seem to be the greatest of friendships, for they are made one not only in the act of fleshly union—which brings about a pleasant association even among animals—but also in the fellowship of the whole way of life within the home [5].

What the Catechism calls the “good of the spouses,” and Gaudium et Spes calls variously “mutual help,” “intimate union,” and “mutual gift,” Aquinas calls friendship. But what could Aquinas possibly mean when he speaks of marriage as the “greatest of friendships”? 

B. Sharing in Perfect Friendship

Aquinas defines friendship as one would expect, speaking of those who are united in a relationship of love: “we say friendship is benevolence with corresponding requital inasmuch as the one loving is loved in return, for friendship has a kind of exchange of love after the manner of commutative justice” [6]. In contrast to an approach that would define friendship primarily in terms of affection or good feeling, perhaps a more typically modern view, friendship is here defined in reference to the will: friendship is that exchange of goodwill that we share with another whom we love. Far from a fleeting passion, friendship is a chosen stance taken up in favor of another; this is in part why Aquinas will speak of friendship as a habit.

Though it may sound strange to think and speak of friendship as a habit—which sounds like something more akin to one’s regular practice of flossing—it makes perfect sense when we understand what we mean when we speak of what Thomas calls a habitus. A habit, classically speaking, is an accidental quality which inheres in a subject in such a way that it becomes like a second nature. It is something “permanent,” and which “does not change easily” [7]. A habitus is a disposition which one possesses to easily and at will perform a particular action; elsewhere St. Thomas will speak of a habits as “principles of activity,” and that they exist as “a kind of medium between potency and act” [8]. To speak of friendship as a habit, then, is to say that friendship is a freely chosen, permanent disposition within the acting person that disposes him well towards another. It is a choice made in love.

As Aquinas says: “mutual love—which belongs to the notion of friendship, as we have indicated—is accompanied by deliberate choice, for this is found only among rational beings. But what is done by choice is not done from passion but rather from habit. Therefore friendship is a habit” [9]. It is not a passing fancy, an emotion or a passion upon which we rely for our feelings of attraction and commitment. Neither is it instinctual, or involuntary, merely an animal response to stimuli which we cannot possibly hope to avoid or overcome. In either of these cases, love and friendship would not be a habit. Now it is true that a habit acts as a kind of second nature by which we come to find certain activities to be easy and almost natural, but it is still something that must be specifically chosen, lovingly cultivated, and deliberately acted upon. Love for a friend, or for a spouse, dwells within us like a flame; it is true that it must be tended, but perfect friendship is a stubborn thing to extinguish.

Now if we are to speak of marriage as friendship, we must be honest and say that there are plenty of marriages which do not seem to exhibit all the qualities of friendship, especially if we are to take the definition of Aquinas that marriage is the “greatest” of friendships. There are plenty of marriages that we would even wish to describe as good and healthy which do not seem to live up to this high standard; indeed, Canon Law says nothing of friendship in regard to marriage, noting simply that it is consent which brings a marriage into being. Is it still possible to speak of marriage as friendship even in those cases which are less than ideal? I propose that the answer must be yes, though of course with qualification.

With St. Thomas, who himself follows the general path blazed by Aristotle, we have grounds to speak of friendships which are either perfect, or imperfect. Some marriages exhibit the friendship which Aquinas calls imperfect, or incidental, and they would be characterized by the corresponding kinds of love within those friendships. Of those friendships which are imperfect, Aristotle speaks of those which are based on utility, and those which are based on pleasure:

Therefore, of those who love one another for utility, one does not love the other for the other’s sake but for the good they mutually gain. The same is true of those who love each other for pleasure, for friends like these do not love witty people because of their character but because they are pleasant companions. Both those who love for utility love for the good they get and those who love for the sake of pleasantness love for the pleasure they enjoy. These do not love a friend because he is a friend but because he is useful or pleasant. Therefore, these friendships are incidental, for a man is loved not for what he is but for some advantage or pleasure [10].

The friendships characterized by love of pleasure or usefulness are imperfect not because it is wicked to have a useful or pleasurable friend—I am loathe to imagine the kind of spouse that would describe their partner as useless or unpleasant—but they are imperfect because they fail to achieve the object of friendship properly so-called: to love the other as other, to will their good separate from any good received in exchange.

What then is this perfect friendship that is meant to be shared by husband and wife? Is this not some mythological Platonic form to which no-one could possibly live up? The key is to understand what is meant here by “perfect”:

Perfect friendship, however, is friendship between men who are good and resemble one another according to virtue, for those who are alike in virtue wish one another good inasmuch as they are virtuous, and they are virtuous in themselves. But people who wish good to friends for their sake are the truest friends; they do this for the friends themselves, and not for something incidental [11].

Thus one need not be perfect, nor have a perfect spouse, to have perfect friendship; what we mean here by perfect friendship is the kind of friendship which exists between husband and wife, not the degree to which it exists.

Think of a fruit, let’s say, an apple; we would say that a fruit is perfect when it is ripe, when it has achieved the end for which it exists. On the other hand, it seems that we would also be correct to say that one ripe apple could be better than another ripe apple. Both apples could be called perfect in this sense of ripeness, but we could also say that one might be more flavorful, or more beautiful, than the other. Perfection in friendship works this way as well: the perfect friendship is that which exists between those who are good, virtuous, and who wish good to the other; at the same time, it is natural that some of these perfect friendships be better than others on account of some being more perfect in virtue, and thus sharing a higher degree of this friendship.

Now let us not mistake the categorization of marriage as “perfect friendship” as a claim that this is merely what marriage is. It is assuredly not. Marriage is this of course (as we have attempted to show), but marriage is also an indissoluble, covenantal bond by which one voluntarily yokes one’s self to another by means of a vow. We find the necessary elements for the making of a marriage expressed clearly in the relevant section of Canon Law:

The consent of the parties, legitimately manifested between persons qualified by law, makes marriage… Matrimonial consent is an act of the will by which a man and a woman mutually give and accept each other through an irrevocable covenant in order to establish marriage (CCL, Can. 1057, §§1-2).

In addition, as an earlier canon notes, “the essential properties of marriage are unity and indissolubility” (CCL, Can. 1056). The reality that marriage is meant to exist as a friendship does not mean that its existence as a legally and morally binding union which cannot be dissolved is to be marginalized. If it were, then marriage could easily be seen as a union which in fact could be dissolved if the bonds of friendship deteriorate.

Thus, when a couple does not understand that their marriage is a special kind of relation established by an indissoluble bond—in addition to the reality that its meant to be a sharing in the best kind of friendship—the couple might mistakenly believe that their marriage could be dissolved if their sharing in friendship dissolves. All the aforementioned aspects of marriage must be affirmed since friendships can, and do, often break down. What is more, those whose marriages are characterized more by the shared goods of usefulness and pleasure are even more likely to undergo this kind of crisis since this kind of friendship is objectively more tenuously held.

Aquinas speaks quite bluntly of the dissolution of these kinds of friendships: “Since men do not always remain the same, friendships of this kind are easily dissolved; when those who are loved cease to be pleasant or useful, their friends stop loving them… if the reason for friendship no longer exists, the friendship itself is dissolved” [12]. When the friendship is no longer “useful,” the friendship is put aside; what need has one for a tool which no longer fills the role for which it was once needed? The dissolution of such a union is often seen today as agreeable, practically a necessity; no-fault divorce allows the vicious cycle of coupling-uncoupling to continue unabated.

Perhaps even more frequent are those marriages based purely on pleasure, in which one’s spouse is seen primarily through the lens of enjoyment. This manner of distortion of the basic dynamic between spouses often crops up when a spouse is viewed as a kind of “soul mate,” by which one’s life (and very existence) is only made complete by this single other person. Most tenuous would seem to be those who marry solely to enjoy the physical beauty of the other; one can easily see how fragile a marriage such as this would be. “When beauty fades,” says Aristotle, “the friendship sometimes breaks up, because the lover is no longer attracted by the beloved and the other no longer receives the adulation of the lover” [13]. I sincerely doubt either Aquinas or Aristotle would deny that the appreciation of beauty has no place within marriage (though Aquinas of course never married, Aristotle himself ended up marrying a princess).

Aquinas maintains, however, that if a relationship is based solely on pleasure, it is all the more susceptible to dissolution. As he notes: “the lover takes pleasure in seeing the beauty of the beloved; and the beloved in receiving favors from the lover. On the termination of these circumstances, pleasurable friendship sometimes breaks up when the attractiveness of the one and the favor of the other cease” [14]. Recognition that the bond of marriage is meant to take up all the various aspects and degrees of friendship is essential; usefulness, pleasure, virtue, love, all these can—and should—be aspects of a healthy marriage.

C. Conclusion

To sum up, because of his characterization of marriage as friendship, he is able to properly interpret the nature of marriage, what kind of relationship it is, and the various characteristics proper to it. By establishing that marriage is is covenant bond brought into existence by the free exchange of consent between man and woman, we saw how it is that St. Thomas is able to call marriage a kind of friendship. Aquinas proposes—and we agree—that marriage should be the pinnacle of friendship, and that even though marriage often falls short of this ideal, friendship is still the proper and most fitting category in which to place the relation between husband and wife. As friendship, the bond between spouses is a bond of love; while it is not the case that love is always and everywhere perfect wherever there is marriage (as we have already discussed), it is only in and through love that we understand the true nature of marriage and to what the spouses are called in their partnership.


[1] Inter virum autem et uxorem maxima amicitia esse videtur (Aquinas, Summa Contra Gentiles, III.2, 123.6). Latin texts of Aquinas’ corpus taken from the online database run by the Dominican House of Studies (; translation my own.

[2] Gaudium et Spes [“Pastoral Constitution on the Church in the Modern World”] in Vatican II Documents (Vatican City: Libreria Editrice Vaticana, 2011), §48.1.

[3] Gaudium et Spes, §48.1.

[4] The Catechism speaks of marriage as “by its nature ordered toward the good of the spouses and the procreation and education of offspring” (CCC, §1601).

[5] SCG III.2, 123.6; my translation.

[6] Aquinas, Nicomachean Ethics Commentary, trans. by C.I. Litzinger (South Bend, IN:Dumb Ox Books, 1993), §1559. Quotations of both Aquinas and Aristotle are taken from this commentary.

[7] Aquinas, NE Comm., §1577.

[8] ST I, 87.2, s.c. and resp.

[9] Aquinas, NE Comm., §1603.

[10] Aristotle, NE Comm., §1565-1566.

[11] Aristotle, NE Comm., §1574-1576.

[12] Aquinas, NE Comm., §1567.

[13] Aristotle, NE Comm., §1587.

[14] Aquinas, NE Comm., §1587.