Objection 1. It would seem that this is false: "Christ as Man is a creature," or "began to be." For nothing in Christ is created except the human nature. But this is false: "Christ as Man is the human nature." Therefore this is also false; Christ as Man is a creature.
Objection 2. Further, the predicate is predicated of the term placed in reduplication, rather than of the subject of the proposition; as when I say: "A body as colored is visible," it follows that the colored is visible. But as stated (8,9) we must not absolutely grant that "the Man Christ is a creature"; nor consequently that "Christ as Man is a creature."
Objection 3. Further, whatever is predicated of a man as man is predicated of him "per se" and simply, for "per se" is the same as "inasmuch as itself," as is said Metaph. v, text. 23. But this is false: "Christ as Man is per se and simply a creature." Hence this, too, is false; "Christ as Man is a creature."
On the contrary, Whatever is, is either Creator or creature. But this is false: "Christ as Man is Creator." Therefore this is true: "Christ as Man is a creature."
I answer that, When we say "Christ as Man" this word "man" may be added in the reduplication, either by reason of the suppositum or by reason of the nature. If it be added by reason of the suppositum, since the suppositum of the human nature in Christ is eternal and uncreated, this will be false: "Christ as Man is a creature." But if it be added by reason of the human nature, it is true, since by reason of the human nature or in the human nature, it belongs to Him to be a creature, as was said (8).
It must however be borne in mind that the term covered by the reduplication signifies the nature rather than the suppositum, since it is added as a predicate, which is taken formally, for it is the same to say "Christ as Man" and to say "Christ as He is a Man." Hence this is to be granted rather than denied: "Christ as Man is a creature." But if something further be added whereby [the term covered by the reduplication] is attracted to the suppositum, this proposition is to be denied rather than granted, for instance were one to say: "Christ as 'this' Man is a creature."
Reply to Objection 1. Although Christ is not the human nature, He has human nature. Now the word "creature" is naturally predicated not only of abstract, but also of concrete things; since we say that "manhood is a creature" and that "man is a creature."
Reply to Objection 2. Man as placed in the subject refers to the suppositum--and as placed in the reduplication refers to the nature, as was stated above. And because the nature is created and the suppositum uncreated, therefore, although it is not granted that "this man is a creature," yet it is granted that "Christ as Man is a creature."
Reply to Objection 3. It belongs to every man who is a suppositum of human nature alone to have his being only in human nature. Hence of every such suppositum it follows that if it is a creature as man, it is a creature simply. But Christ is a suppositum not merely of human nature, but also of the Divine Nature, in which He has an uncreated being. Hence it does not follow that, if He is a creature as Man, He is a creature simply.
Source: Summa Theologica (New Advent)