Objection 1. It would seem that this is true: "Christ is a creature." For Pope Leo says [Cf. Append. Opp. August., Serm. xii de Nativ.]: "A new and unheard of covenant: God Who is and was, is made a creature." Now we may predicate of Christ whatever the Son of God became by Incarnation. Therefore this is true; Christ is a creature.
Objection 2. Further, the properties of both natures may be predicated of the common hypostasis of both natures, no matter by what word they are signified, as stated above (Article 5). But it is the property of human nature to be created, as it is the property of the Divine Nature to be Creator. Hence both may be said of Christ, viz. that He is a creature and that he is uncreated and Creator.
Objection 3. Further, the principal part of a man is the soul rather than the body. But Christ, by reason of the body which He took from the Virgin, is said simply to be born of the Virgin. Therefore by reason of the soul which is created by God, it ought simply to be said that He is a creature.
On the contrary, Ambrose says (De Trin. i): "Was Christ made by a word? Was Christ created by a command?" as if to say: "No!" Hence he adds: "How can there be a creature in God? For God has a simple not a composite Nature." Therefore it must not be granted that "Christ is a creature."
I answer that, As Jerome [Gloss, Ord. in Hosea 2:16] says, "words spoken amiss lead to heresy"; hence with us and heretics the very words ought not to be in common, lest we seem to countenance their error. Now the Arian heretics said that Christ was a creature and less than the Father, not only in His human nature, but even in His Divine Person. And hence we must not say absolutely that Christ is a "creature" or "less than the Father"; but with a qualification, viz. "in His human nature." But such things as could not be considered to belong to the Divine Person in Itself may be predicated simply of Christ by reason of His human nature; thus we say simply that Christ suffered, died and was buried: even as in corporeal and human beings, things of which we may doubt whether they belong to the whole or the part, if they are observed to exist in a part, are not predicated of the whole simply, i.e. without qualification, for we do not say that the Ethiopian is white but that he is white as regards his teeth; but we say without qualification that he is curly, since this can only belong to him as regards his hair.
Reply to Objection 1. Sometimes, for the sake of brevity, the holy doctors use the word "creature" of Christ, without any qualifying term; we should however take as understood the qualification, "as man."
Reply to Objection 2. All the properties of the human, just as of the Divine Nature, may be predicated equally of Christ. Hence Damascene says (De Fide Orth. iii, 4) that "Christ Who God and Man, is called created and uncreated, passible and impassible." Nevertheless things of which we may doubt to what nature they belong, are not to be predicated without a qualification. Hence he afterwards adds (De Fide Orth. iv, 5) that "the one hypostasis," i.e. of Christ, "is uncreated in its Godhead and created in its manhood": even so conversely, we may not say without qualification, "Christ is incorporeal" or "impassible"; in order to avoid the error of Manes, who held that Christ had not a true body, nor truly suffered, but we must say, with a qualification, that Christ was incorporeal and impassible "in His Godhead."
Reply to Objection 3. There can be no doubt how the birth from the Virgin applies to the Person of the Son of God, as there can be in the case of creation; and hence there is no parity.
Source: Summa Theologica (New Advent)