Matthew 13:55

And this was the carpenter's son who subdues iron by means of fire, who tries the virtue of this world in the judgment, and forms the rude mass to every work of human need; the figure of our bodies, for example, to the divers ministrations of the limbs, and all the actions of life eternal.

How then, one may say, are James and the others called His brethren? In the same kind of way as Joseph himself was supposed to be husband of Mary. For many were the veils provided, that the birth, being such as it was, might be for a time screened. Wherefore even John so called them, saying, "For neither did His brethren believe in Him."

"Is not this the carpenter's son?" The greater then the marvel, and the more abundant the ground of amaze. "Is not His mother called Mary, and His brethren James, and Joses, and Simon, and Judas? and His sisters, are they not all with us? Whence hath this man these things? And they were offended in Him." Seest thou that Nazareth was where He was discoursing? "Are not his brethren," it is said, "such a one, and such a one?" And what of this? Why, by this especially you ought to have been led on to faith. But envy you see is a poor base thing, and often falls foul of itself. For what things were strange and marvellous, and enough to have gained them over, these offended them.

(in Helvid. 14.) Those who are here called the Lord's brethren, are the sons of a Mary, His Mother's sister; she is the mother of this James and Joseph, that is to say, Mary the wife of Cleophas, and this is the Mary who is called the mother of James the Less.

And when they are mistaken in His Father, no wonder if they are also mistaken in His brethren. Whence it is added, Is not his mother Mary, and his brethren, James, and Joseph, and Simon, and Judas? And his sisters, are they not all with us?