Feast of the Circumcision—Octave of Christmas Solemnity of the Mother of God
Today's Mass deals, first of all with the Circumcision of our Lord. This was the ritual by which Jewish men were marked as members of God's people. There is a sacrificial dimension to it—a letting of blood—that suggests an offering for the forgiveness of sins. St. Ambrose suggests that our Lord's Circumcision, on the 8th day after His birth, is a sign that the ultimate forgiveness of sin—the redemption of mankind—would come on the 8th day; that is the day of our Lord's Resurrection.
The rite of circumcision was to the Old Testament as Baptism is to the New. Baptism is our outward sign, effecting the forgiveness of sin, and marking us as God's people. So this feast of Our Lord might well remind us of the baptismal promises that were made in our name; of the obligation that we have to live the Faith internally and to profess it externally; and of the joy that our families felt, together with the joy felt by the angels and saints on the day of our Baptism. In short, it might be a sort of day of re-dedication to the ideals of our Baptism.
This feast is also referred to as the Octave Day of Christmas. The Church keeps her major festivals with an octave, a week-long celebration, and Christmas is no exception. This is important to recognize in our modern, commercial culture, where the merchants were trying to get us to celebrate Christmas back during Advent, and would now like to get us to quickly forget it in preparation for the next money spending season of the year. We ought not to forget about our Lord's birth so quickly! Indeed the Church has us celebrate the events of our Lord's infancy and childhood until the feast of His Presentation in the Temple on February 2nd. So don't be in a hurry to forget the infant Child of Bethlehem.
Finally, the feast begins the new year with devotion to our Blessed Lady as Mother of God. This is not a modern innovation—look in your old missal and read the “collect”—but perennial devotion, recognizing that Mary was much more than the mother of a mere man, but was in fact the Mother of the God-man. It should set a pattern of devotion for us for the coming year—all devotion to Jesus Christ needs an element of devotion to His Blessed Mother.
Since this is the new year, the Church has us end this Mass with an invocation of the Holy Ghost; that everything we do during the coming year will be formed in holiness and the grace of God. A plenary indulgence is granted under the usual conditions.
So this new year begins today with the feast of the Circumcision, the Octave of Christmas, and the Solemnity of the Mother of God—a day of rededication and continued Christmas joy, under the protection of the Blessed Virgin Mother of God and the Holy Ghost, her Divine Spouse.