The story of Moses is a famous one. Moses is appointed to set the captives free. After a lengthy back and forth session of “let my people go” and “oh no I wont”. Finally it came to a head and a sacrifice was made.
The sacrifice was that of a lamb or a firstborn. There was a choice – either the lamb is sacrificed or the firstborn of the family is sacrificed. The Lord gave instructions on how this would work – he wanted to set his people free and the only way they would be free is if blood is shed. A sacrifice is to be made and either the Lord would provide and you trust in his provision or you pay the price yourself.
The people were to eat a lamb and:
“Then they shall take some of the blood and put it on the two doorposts and the lintel of the houses in which they eat it. (Exodus 12:7)
The house they were in was to be covered in the blood:
“The blood shall be a sign for you, on the houses where you are. And when I see the blood, I will pass over you, and no plague will befall you to destroy you, when I strike the land of Egypt. (Exodus 12:13)
If they are under the covering of the blood they will not be harmed. The blood saves them and they were either in the covering or not. They could not add to the covering, they just needed to stay under it and know they were safe.
On the cross the Son of God, the lamb, shed his blood and all those covered in his blood shall not be harmed on the day of judgement, but they will be passed over.
Christmas is about the blood of Jesus covering us.