Alimentum Pacis: The Eucharist and Peace in St. Thomas Aquinas

Thomas Aquinas’s theology of peace rarely receives the attention it deserves in current scholarship.¹ This might give someone following the secondary literature the impression that Aquinas either is unconcerned with peace or has nothing noteworthy to say. However, this would be far from the truth. Aquinas was quite concerned with peace. For example, commenting on the Psalm 33, he states that, if your neighbor is fighting against you, “then it belongs to you to seek peace,” and if your neighbor is seeking peace with you, then “you should pursue it too.”² In another place, he calls peace “intensely enjoyable.”³ He even calls peace the last of all goods and the general end (finis) of the mind.⁴ Indeed, according to Aquinas, all desire peace. Every single person, by desiring anything, de facto desires peace.⁵ These examples alone show both that Aquinas is concerned with peace and that the secondary literature has failed to explore some noteworthy claims by Aquinas.

The purpose of this article is not an exhaustive treatment of peace in St. Thomas. Its purpose is much more circumscribed: to explore and expose the connections between supernatural peace and the Eucharist in the thought of Aquinas and thereby fill a lacuna in English Thomistic literature.⁶ Put simply, the thesis of this paper is that, since the Eucharist is our re-presentation of and participation in the sacrifice of Christ on the Cross and the very sustenance of charity, it is both the cause of and the nourishment for true peace (the right order found preeminently in Christ himself). In short, according to Aquinas, the Eucharist efficiently and exemplarily causes peace because it efficiently and exemplarily causes charity, the direct efficient cause of peace.⁷ Such a conception between peace and the Eucharist deserves renewed attention not only because the connection between peace and the Eucharist is traditional in Christianity (indeed, one of the traditional names for the Eucharist is “peace”), but also because it both brings another interlocutor to current debates over the nature and cause of peace and sheds a different light over the whole Thomistic moral synthesis, a synthesis seeking peace.⁸

The Ratio of Peace

In beginning to explore the connections between peace and the Eucharist, it is necessary first to specify what Aquinas means by peace. Scanning the Thomistic corpus, one finds many different definitions: the removal of impediments to attaining the good, rest of the will in the fullness of good and immunity from all evil, putting things in right order, harmony with ourselves and others, the quiet of the mind in the end, ordered harmony, security against the loss of goods, tranquility of mind, tranquility arising from order, and the cessation of all desire.⁹ Yet, Aquinas’s most common definition by far is borrowed from Augustine: “tranquility of order.”¹⁰ It is likewise under this definition that all the others can be subsumed.¹¹

While tranquility and order constitute peace together, the causally prior of these two elements is order. Tranquility is dependent on order, but not vice versa. What Aquinas means by “order” is a kind of relation and unity of parts based on a reference to a common good that organizes and unites them as principle of that order.¹² Put simply, there can be no peace without some kind of proper order, the proper relation of humans to each other, to God, and within themselves.¹³ The second central concept is tranquility or rest (quietudine). This denotes not only the lack of conflict caused by proper order (within oneself, between people, and with God) but also the rest of all psychological faculties in the good. In short, there can be no peace if the heart remains restless. In fact, the two aspects of peace, tranquility and order, are so interdependent that Aquinas often gives only one element of the standard Augustinian definition. One cannot have proper order without it producing tranquility, and tranquility is only truly and lastingly found in proper order.

On the basis of this ratio, ordered...