Jesus is the Lord

Luke 2:15-24
Shephers went with haste and found Mary and Joseph and they baby lying in a manger. When they saw it, they made known the saying that had been told them concerning this child.
But Mary treasured up all these things, pondering them in her heart.
At the eight days, when he was circumcised, he was called Jesus, the name given by the angel before he was conceived in the womb.
Jesus presented at the Temple for offer a sacrifice. He is the first born in Joseph's home.
Why?
Mary and Joseph follow the Law of the Lord to purify themselves.
Mary knew what she born is, she pondered what the shephers said about this child. She treasured these things. This is unusual thing.
How?
Jesus is the Lord, who came down to the world in flesh to erase our sins.