Luke 2:21

As we have died with Him at His death, and risen together with Him at His resurrection, so with Him have we been circumcised, and therefore need not now circumcision in the flesh. But the name of Jesus, a glorious name and worthy of all honour, a name which is above every other, ought not first to be uttered by men, nor by them be brought into the world. Therefore significantly the Evangelist adds, which was called of the Angel, &c.

(De Sabbato et Circumcisione.) For circumcision expressed nothing else, but the stripping off of the old birth, seeing that part was circumcised which caused the birth of the body. And thus it was done at that time as a sign of the future baptism through Christ. Therefore as soon as that of which it was a sign came, the figure ceased. For since the whole of the old man Adam is taken away by baptism, there remains nothing which the cutting of a part prefigures.

Who is this Child, but He of whom it was said, Unto us a child is born, unto us a son is given? (Is. 9:6, Gal. 4:5.) For He was made under the law, that He might redeem them who were under the law.

(lib. i. Hær. 30.) Now the followers of Ebion and Cerinthus say e, "It is enough for a disciple if he be as his Master. But Christ circumcised Himself. Be thou therefore circumcised." But herein do they deceive themselves, destroying their own principles; for if Ebion should confess that Christ as God descended from heaven and was circumcised on the eighth day, it might then afford the ground of an argument for circumcision; but since he affirms Him to be mere man, surely as a boy he cannot be the cause of Himself being circumcised, as neither are infants the authors of their own circumcision. But we confess that it is God Himself who has descended from heaven, and that inclosed in a virgin's womb, He abode there the whole time necessary for her delivery, until He should perfectly form to Himself of the virgin's womb a human body; and that in this body He was not in appearance but truly circumcised on the eighth day, in order that the figures having come to this spiritual fulfilment, both by Himself and His disciples, might now be spread abroad no longer the figures but the reality. (ubi sup.) Christ was circumcised for several reasons. First indeed to show the reality of His flesh, in opposition to Manichæus f and those who say that He came forth in appearance only. Secondly, that He might prove that His body was not of the same substance with the Deity, according to Apollinaris, and that it descended not from heaven, as Valentinian said. Thirdly, to add a confirmation to circumcision which He had of old instituted to wait His coming. Lastly, to leave no excuse to the Jews. For had He not been circumcised, they might have objected that they could not receive Christ uncircumcised.

It was the custom on the eighth day to perform the circumcision of the flesh. For on the eighth day Christ rose from the dead, and conveyed to us a spiritual circumcision, saying, Go and teach all nations, baptizing them. (Matt. 28:19.) But according to the command of the law, on the same day He received the imposition of a name, as it follows, His name was called Jesus, which is interpreted Saviour. For He was brought forth for the salvation of the whole world, which by His circumcision He prefigured, as the Apostle says to the Colossians, "Ye are circumcised with a circumcision made without hands, in the stripping off of the body of the flesh, to wit, the circumcision of Christ." (Col. 2:11.)