Aquinas on Deification - Some Texts

Julianna asks with regard to my previous post about the specific passages on which what I said about St Thomas Aquinas’s teaching on theosis is based. Here are a few passages which I think bring out Aquinas’s teaching very clearly, though they are by no means the only ones.

The leading expert on the theme of deification in Aquinas is Daniel A. Keating, who has recently written a book entitled Deification and Grace (Sapientia Press) which traces the outlines of a theology of theosis within the Catholic tradition.

Anyway, here are some very rich texts from St Thomas…

Commentary on Ephesians (on Eph. 3:20):

the human mind and will could never imagine, understand or ask that God become man, and that man become God and a sharer in the divine nature. But he has done this in us by his power, and it was accomplished in the Incarnation of his Son. “That through this you may be made partakers of the divine nature” (2 Pet. 1:4).

Commentary on John (on John 15:9)

the Son did not love the disciples in either of these ways. For he did not love them to the point of their being gods by nature, nor to the point that they would be united to God so as to form one person with him. But he did love them up to a similar point: he loved them to the extent that they would be gods by their participation in grace – “I say, ‘You are gods’” (Ps 82:6); “He has granted to us precious and very great promises, that through these you may become partakers of the divine nature” (2 Pet 1:4) ‑ and he loved them to the extent that they would be united to God in affection: “He who is united to the Lord becomes one spirit with him” (1 Cor 6:17); “For those whom he foreknew he also predestined to be conformed to the image of his Son" (Rom 8:29). Thus the Father communicated to the Son a greater good, with respect to each nature of the Son, than the Son did to his disciples; yet there is a similarity, as was said.

Commentary on Romans (on Rom. 8:29)

Then [Paul] indicates what follows from this predestination, when he says: “in order that he might be the first-born among many brethren”. For just as God willed to communicate His natural goodness to others by imparting to them a likeness of his goodness, so that he is not only good but the author of good things, so the Son of God willed to communicate to others conformity to his sonship, so that he would not only be the Son but the first-born among sons. Thus, he who is the only-begotten through an eternal origin, as it says in Jn (1:18): “The only Son who is in the bosom of the Father,” is the first-born among many brethren by the bestowal of grace: “He is the first-born of the dead, and ruler of kings on earth” (Rev 1:5). Therefore, Christ has us as brothers, both because he communicated to us a likeness of his sonship and because he assumed the likeness of our nature, as it says in Heb (2:17): “He had to be made like his brethren in every respect.”

Summa Theologiae (I-II, q. 112, a. 1)

Nothing can act beyond its species, since the cause must always be more powerful than its effect. Now the gift of grace surpasses every capability of created nature, since it is nothing short of a partaking of the divine nature, which exceeds every other nature. And thus it is impossible that any creature should cause grace. For it is as necessary that God alone should deify, bestowing a partaking of the divine nature by a participated likeness, as it is impossible that anything save fire should enkindle.