Ambrose of Milan — as excerpted in the Catena Aurea on Luke 1:11-14

“But a saint is not only the blessing of his parents, but also the salvation of many; as it follows, And many shall rejoice at his birth. Parents are reminded here to rejoice at the birth of saints, and to give thanks. For it is no slight gift of God to vouchsafe unto us children, to be the transmitters of our race, to be the heirs of succession.”