The Human Flesh and Bones of Christ

Summa Contra Gentiles, Book IV, chapter 30

In this chapter, St. Thomas confronts the heresy that Christ’s body came from heaven, rather than from the Blessed Mother.

(The preceding chapter had already addressed the false presupposition of this idea, namely that all earthly things are completely evil.)

Then St. Thomas deals with the even weirder idea that the eternal Word became flesh by changing into flesh.

Summa Contra Gentiles, Book IV, chapter 31