Agere Sequitur Esse

Cause of the Formation of Christ’s Body

Since the formation of the human body is naturally effected by the male seed, any other way of fashioning the body of Christ was above nature. God alone is the author of nature, and He works supernaturally in natural things, as was remarked above. Hence we conclude that God alone miraculously formed that body from matter supplied by human nature. However, although every action of God in creation is common to the three divine persons, the formation of Christ’s body is, by a certain appropriation, attributed to the Holy Spirit. For the Holy Spirit is the love of the Father and the Son, who love each other and us in Him. Since God decreed that His Son should become incarnate because of “His exceeding charity with which He loved us,” as the Apostle says in Ephesians 2:4, the formation of Christ’s flesh is fittingly ascribed to the Holy Spirit.

Besides, the Holy Spirit is the author of all grace, since He is the first in whom all gifts are given gratis. But the taking up of human nature into the unity of a divine person was a communication of superabundant grace, as is clear from what was said above. Accordingly, to emphasize the greatness of this grace, the formation of Christ’s body is attributed to the Holy Spirit.

Another reason for the appropriateness of this teaching is the relationship between the human word and spirit. The human word, as existing in the heart, bears a resemblance to the eternal Word as existing in the Father. And as the human word takes voice that it may become sensibly perceptible to men, so the Word of God took flesh that it might appear visibly to men. But the human voice is formed by man’s breath or spirit. In the same way the flesh of the Word of God ought to have been formed by the Spirit of the Word.

Reference

St. Thomas Aquinas. (1265-1274). Compendium Theologiae: Cause of the Formation of Christ’s Body, trans. by Cyril Vollert. St. Louis & London: B. Herder Book Co., 1947