Mark 14:12-16, 22-26
Passover celebrated Israel's exodus from Egypt. God had inflicted nine plagues on the Egyptians and was preparing for the tenth plague—the death of the firstborn. God commanded the people of Israel to sacrifice a lamb for each family and to sprinkle the blood of the lamb on the doorposts and lintel so that the death angel, seeing the blood, would pass over the Israelites' houses and leave the firstborn untouched (Exodus 12-13).