Reply Obj. 1: As was said above (A. 1), the soul of Christ is said to be the medium in the union of the flesh with the Word, in the order of nature; but it does not follow from this that it was the medium in the order of time.
Reply Obj. 2: As Pope Leo says in the same Epistle, Christ's soul excels our soul "not by diversity of genus, but by sublimity of power"; for it is of the same genus as our souls, yet excels even the angels in "fulness of grace and truth." But the mode of creation is in harmony with the generic property of the soul; and since it is the form of the body, it is consequently created at the same time that it is infused into and united with the body; which does not happen to angels, since they are substances entirely free from matter.
Reply Obj. 3: Of the fulness of Christ all men receive according to the faith they have in Him; for it is written (Rom. 3:22) that "the justice of God is by faith of Jesus Christ unto all and upon all them that believe in Him." Now just as we believe in Him as already born; so the ancients believed in Him as about to be born, since "having the same spirit of faith . . . we also believe," as it is written (2 Cor. 4:13). But the faith which is in Christ has the power of justifying by reason of the purpose of the grace of God, according to Rom. 4:5: "But to him that worketh not, yet believeth in Him that justifieth the ungodly, his faith is reputed to justice according to the purpose of the grace of God." Hence because this purpose is eternal, there is nothing to hinder some from being justified by the faith of Jesus Christ, even before His soul was full of grace and truth. _______________________
FOURTH ARTICLE [III, Q. 6, Art. 4]
Whether the Flesh of Christ Was Assumed by the Word Before Being
United to the Soul?
Objection 1: It would seem that the flesh of Christ was assumed by the Word before being united to the soul. For Augustine [*Fulgentius] says (De Fide ad Petrum xviii): "Most firmly hold, and nowise doubt that the flesh of Christ was not conceived in the womb of the Virgin without the Godhead before it was assumed by the Word." But the flesh of Christ would seem to have been conceived before being united to the rational soul, because matter or disposition is prior to the completive form in order of generation. Therefore the flesh of Christ was assumed before being united to the soul.
Obj. 2: Further, as the soul is a part of human nature, so is the body. But the human soul in Christ had no other principle of being than in other men, as is clear from the authority of Pope Leo, quoted above (A. 3). Therefore it would seem that the body of Christ had no other principle of being than we have. But in us the body is begotten before the rational soul comes to it. Therefore it was the same in Christ; and thus the flesh was assumed by the Word before being united to the soul.
Obj. 3: Further, as is said (De Causis), the first cause excels the second in bringing about the effect, and precedes it in its union with the effect. But the soul of Christ is compared to the Word as a second cause to a first. Hence the Word was united to the flesh before it was to the soul.
On the contrary, Damascene says (De Fide Orth. iii, 2): "At the same time the Word of God was made flesh, and flesh was united to a rational and intellectual soul." Therefore the union of the Word with the flesh did not precede the union with the soul.
I answer that, The human flesh is assumable by the Word on account of the order which it has to the rational soul as to its proper form. Now it has not this order before the rational soul comes to it, because when any matter becomes proper to any form, at the same time it receives that form; hence the alteration is terminated at the same instant in which the substantial form is introduced. And hence it is that the flesh ought not to have been assumed before it was human flesh; and this happened when the rational soul came to it. Therefore since the soul was not assumed before the flesh, inasmuch as it is against the nature of the soul to be before it is united to the body, so likewise the flesh ought not to have been assumed before the soul, since it is not human flesh before it has a rational soul.