
Augustine of Hippo
Catena Aurea · Lukasevangelium 1
And in the sixth month the angel Gabriel was sent from God unto a city of Galilee, named Nazareth, To a virgin espoused to a man whose name was Joseph, of the house of David; and the virgin’s name was Mary.
(de san. Virg. cap. vi.) To a virgin, for Christ could be born from virginity alone, seeing He could not have an equal in His birth. It was necessary for our Head by this mighty miracle to be born according to the flesh of a virgin, that He might signify that his members were to be born in the spirit of a virgin Church.