That Joseph should not suppose that he was no longer needed in this wedlock, seeing the conception had taken place without his intervention, the Angel declares to him, that though there had been no need of him in the conception, yet there was need of his guardianship; for the Virgin should bear a Son, and then he would be necessary both to the Mother and her Son; to the Mother to screen her from disgrace, to the Son to bring Him up and to circumcise Him. The circumcision is meant when he says, “And thou shalt call His name Jesus;” for it was usual to give the name in circumcision.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: ap Anselm