After the annual celebration of the paschal mystery (Easter), the church has no more ancient custom than celebrating the memorial of the nativity of the Lord and of his first manifestations, and this takes place in Christmas time.
At Mass over the Christmas Season you will hear some of the following passages from scripture:
The virgin will conceive and give birth to a son and they shall call him Emmanuel.
I bring you news of great joy. This day a child is born for us, a song given to us.
The shepherds find Mary and Joseph and the baby, and glorified God.
The word was made flesh, he lived among us, and we saw his glory.
All of these versus bring to us the knowledge that the Lord give to us, through Mary a child that would ultimately free us from all our sins.