Gregory the Great — as excerpted in the Catena Aurea on Matthew 12:46-50

“(Hom. in Ev. iii. 2.) The Lord deigned to call faithful disciples His brethren, saying, Go, tell my brethren. Since then a man may be made a brother of the Lord by coming to the faith, it should be enquired how one may become also His mother. Be it known by us then, that he that by believing is made brother or sister of Christ, becomes His mother by preaching; for in pouring Him into the heart of the hearer, he may be said to beget the Lord; and he is made the Lord’s mother, when by his word love of the Lord is begotten in the mind of his neighbour.”