Troparion of the Feast Tone 1
Thou Who art by nature God, didst without change take human form,/ O most compassionate Lord,/ and in fulfilling the Law of Thine own will didst receive circumcision in the flesh,/ to banish hades and roll away the veil of our passions./ Glory to Thy goodness; glory to Thy compassion;/ glory to Thy condescension, O Word.
Another Troparion of the Feast Tone 1
Thou Who sittest with the Father/ on a fiery throne in the heights/ wast pleased to be born of a Virgin through the Divine Spirit on earth./ Wherefore Thou wast circumcised as a man on the eighth day./ Glory to Thine all-gracious will; glory to Thy providence;/ glory to Thy condescension, O only Lover of mankind.
Kontakion of the Feast Tone 3
In undergoing clrcumcision/ the Lord of all has circumcised the sins of mortal men./ On this day He gives salvation to the world./ And the Hierarch Basil, the Creator’s lightbearer/ and Christ’s mystic, rejoices in the highest.
Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ. For in him dwelleth all the fulness of the Godhead bodily. And ye are complete in him, which is the head of all principality and power: In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ: Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead.
Luke 2:20-21, 40-52
And the shepherds returned, glorifying and praising God for all the things that they had heard and seen, as it was told unto them. And when eight days were accomplished for the circumcising of the child, his name was called JESUS, which was so named of the angel before he was conceived in the womb. And the child grew, and waxed strong in spirit, filled with wisdom: and the grace of God was upon him. Now his parents went to Jerusalem every year at the feast of the passover. And when he was twelve years old, they went up to Jerusalem after the custom of the feast. And when they had fulfilled the days, as they returned, the child Jesus tarried behind in Jerusalem; and Joseph and his mother knew not of it. But they, supposing him to have been in the company, went a day’s journey; and they sought him among their kinsfolk and acquaintance. And when they found him not, they turned back again to Jerusalem, seeking him. And it came to pass, that after three days they found him in the temple, sitting in the midst of the doctors, both hearing them, and asking them questions. And all that heard him were astonished at his understanding and answers. And when they saw him, they were amazed: and his mother said unto him, Son, why hast thou thus dealt with us? behold, thy father and I have sought thee sorrowing. And he said unto them, How is it that ye sought me? wist ye not that I must be about my Father’s business? And they understood not the saying which he spake unto them. And he went down with them, and came to Nazareth, and was subject unto them: but his mother kept all these sayings in her heart. And Jesus increased in wisdom and stature, and in favour with God and man.
From the OCA website:
The Circumcision of the Lord: On the eighth day after His Nativity, our Lord Jesus Christ, in accordance with the Old Testament Law, accepted circumcision, which was decreed for all male infants as a sign of the Covenant of God with the Forefather Abraham and his descendants (Gen 17:10-14, Lev 12:3). Upon the performing of this ritual the Divine Infant was given the name Jesus, as the Archangel Gabriel declared on the day of the Annunciation to the Most Holy Theotokos (Lk 1:31-33, 2:21). The Fathers of the Church explain that the Lord, the Creator of the Law, accepted circumcision in order to give people an example how faithfully the divine ordinances ought to be fulfilled. The Lord was circumcised so that later no one would doubt that He had truly assumed human flesh, and that His Incarnation was not merely an illusion, as certain heretics (Docetists) taught.
In the New Testament, the ritual of circumcision gave way to the Mystery of Baptism, which it prefigured (Col 2:11-12). Accounts of the Feast of the Circumcision of the Lord continue in the Eastern Church right up through the fourth century. The Canon of the Feast was written by St. Stephen of the St. Sabbas Monastery (October 28 and July 13).
Together with circumcision, which the Lord accepted as a sign of God’s Covenant with mankind, He also received the Name Jesus (Savior) as an indication of His service, the work of the salvation of the world (Mt 1:21; Mk 9:38-39, 16:17; Lk 10:17; Acts 3:6, 16; Phil 2:9-10). These two events, the Circumcision and Naming, remind Christians that they have entered into a New Covenant with God and “are circumcised with a circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ” (Col 2:11). The very name “Christian” is a sign of mankind’s entrance into a New Covenant with God.