The Church Fathers explain that the Lord, the Creator of the Law, underwent circumcision in order to give people an example of 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.
Additionally, he received the name Jesus (Savior) on this day. These two events, the Lord's Circumcision and Naming, remind Christians that they have entered into a New Covenant with God.
Troparion (Tone 1)
- Enthroned on high with the Eternal Father and Your divine Spirit,
- O Jesus, You willed to be born on earth of the unwedded handmaid, your Mother.
- Therefore You were circumcised as an eight-day old Child.
- Glory to Your most gracious counsel;
- Glory to Your dispensation;
- Glory to Your condescension, O only Lover of mankind.
- The Lord of all accepts to be circumcised,
- Thus, as He is good, excises the sins of mortal men.
- Today He grants the world salvation,
- While light-bearing Basil, high priest of our Creator,
- Rejoices in heaven as a divine initiate of Christ.
- from http://orthodoxwiki.org/Circumcision_of_our_Lord