On the eighth day following His birth, the Divine Child was presented in the Temple and circumcised according to the Law existing in Israel since the time of Abraham. On this occasion He was given the name Jesus, which the Archangel Gabriel had announced to the Most-holy Virgin Mary. The Old Testament circumcision was the prefiguring of the New Testament baptism. The circumcision of our Lord shows that He truly received upon Himself the body of man and not just seemingly, as was later taught of Him by heretics. Our Lord was also circumcised because He wanted to fulfill the entire Law, which He Himself gave through the prophets and forefathers. In fulfilling the written Law, He replaced it with baptism in His Holy Church, as was proclaimed by the Apostle Paul: For in Christ Jesus neither circumcision availeth any thing, nor uncircumcision, but a new creature (Galatians 6:15). (In the liturgical calendar of the Church, this Feast of the Lord’s Circumcision has neither a forefeast nor an afterfeast.)
Source: St. Nikolai Velimirovic, The Prologue of Ohrid – Volume One.
Our human form hast Thou taken on Thyself without change, O greatly-compassionate Master, though being God by nature; fulfilling the Law, Thou willingly receivest circumcision in the flesh, that Thou mightest end the shadow and roll away the veil of our sinful passions. Glory be to Thy goodness unto us. Glory be to Thy compassion. Glory, O Word, to Thine inexpressible condescension.