The Angelic Doctor Against the Errors of the Greeks - Chapter 18

How the assertion that the deity was made is to be understood.

Doubt also arises from another passage of Athanasius in the same letter: “The Godhead made man has conformed the Church to himself through his Spirit.”  Now, the Master in the fifth distinction of the third book of the Sentences  states that the divine nature should not be said to have become flesh, as is said: The Word became flesh. For the statement: The Word became flesh, is made, because the Word was made man. Therefore it should not be said that the divine essence or divinity was made man.

But it is to be observed that the divinity is not said to have been made man because the divine nature was changed into human nature, but was made man in the sense that the divine nature is said to have assumed a human nature in the one person, namely, of the Word. As also the Damascene says that: “the nature of the divinity in one of its persons became incarnate,”  that is, united to flesh.

It should be recognized, however, that it is on a different basis that the Word is said to be man and the divinity is said to be man. For when it is said: The Word is man, the predication  involved is that via information, because the person of the Word subsists in a human nature. But, when it is said: the divinity is man, the predication is not via information, because the human nature does not inform the divine. Rather the predication is via identity, as when it is said: the divine essence is the Father, or: the divine essence is the Son; for man stands for the person of the Word when it is said: the divinity is man. And the same is true when it is said: the divinity is made man, because the person of the Son has begun to be incarnate, a fact implied by the term man, even though the person of the Son did not begin to be. For the deity was always Son, but not always man.