Whether this Man, Christ, began to be?

 

 

We must not say that “this Man”—pointing to Christ—“began to be,” unless we add something. And this for a twofold reason. First, for this proposition is simply false, in the judgment of the Catholic Faith, which affirms that in Christ there is one suppositum and one hypostasis, as also one Person. For according to this, when we say “this Man,” pointing to Christ, the eternal suppositum is necessarily meant, with Whose eternity a beginning in time is incompatible. Hence this is false: “This Man began to be.” Nor does it matter that to begin to be refers to the human nature, which is signified by this word “man”; because the term placed in the subject is not taken formally so as to signify the nature, but is taken materially so as to signify the suppositum, as was said (Article 1, Reply to Objection 4). Secondly, because even if this proposition were true, it ought not to be made use of without qualification; in order to avoid the heresy of Arius, who, since he pretended that the Person of the Son of God is a creature, and less than the Father, so he maintained that He began to be, saying “there was a time when He was not.”

The words quoted must be qualified, i.e. we must say that the Man Jesus Christ was not, before the world was, “in His humanity.”

Thomas Aquinas, Summa Theologica (Part III Question 16, Article 9)