John of Damascus — on Ezek 44:1-2 (An Exposition of the Orthodox Faith (Book IV), Chapter 14)

“But just as He who was conceived kept her who conceived still virgin, in like manner also He who was born preserved her virginity intact, only passing through her and keeping her closed. [Ezekiel 44:2] The conception, indeed, was through the sense of hearing, but the birth through the usual path by which children come, although some tell tales of His birth through the side of the Mother of God. For it was not impossible for Him to have come by this gate, without injuring her seal in anyway. The ever-virgin One thus remains even after the birth still virgin, having never at any time up till death consorted with a man.”