And he that is eight days old shall be circumcised among you, every manchild in your generations, he that is born in the house or bought with money from any stranger who is not of thy seed. (Gn 17:12)
By Mosaic Law, a male child is to be circumcised eight days after birth. If you start counting December 25—the day we choose to celebrate Jesus’ birth, as day one, then the circumcision has to be January 1. The circumcision of a child was, and still is in Jewish households, a time of festivity and the time when the child is given his name, thus, we also celebrate the Naming of Jesus.
When the current hymnal used by the Lutheran church, The Lutheran Service Book, was published, the festival date was changed from January 1, to December 31 and renamed The Eve of the Circumcision and Naming of Jesus.
Circumcision was ordered by God as a physical sign of His covenant. Since Jesus was born to upright Jewish parents, and because He allowed Himself to be placed under the Law, He was circumcised on the eighth day. (Lk 2:21)( Ga 4:4, 5)
According to tradition, this is the first time Jesus’ blood was shed and is a foreshadowing of the blood He shed for us years later. Today, we recognize the circumcision of Jesus and how He fulfilled the Law, and give thanks to God for our Baptism. It is baptism which has supplanted circumcision as an outward symbol of our covenant with God and our freedom from the condemnation of the Law.