This feast commemorates three realities. The Octave day of Christmas is a second celebration of the mystery of our Lord's Nativity. We come to this mystery in a new perspective, still considering the newborn King but now more in relation to his Virgin Mother.
Mary was a virgin before, during, and after giving birth to Jesus. She conceived by the power of the Holy Spirit, gave birth without any pain or labor, and remains a virgin forever.
Finally, this eighth day is the day of our Lord's circumcision. This is the first shedding of his precious blood for our salvation. Also, on this day, the Child is given the Holy Name of Jesus.