Exodus 12:23-30

23For the Lord will pass through to strike the Egyptians, and when he sees the blood on the lintel and on the two doorposts, the Lord will pass over the door and will not allow the destroyer to enter your houses to strike you.

24You shall observe this rite as a statute for you and for your sons forever.

25And when you come to the land that the Lord will give you, as he has promised, you shall keep this service.

26And when your children say to you, 'What do you mean by this service?'

27you shall say, 'It is the sacrifice of the Lord's Passover, for he passed over the houses of the people of Israel in Egypt, when he struck the Egyptians but spared our houses.'" And the people bowed their heads and worshiped.

28Then the people of Israel went and did so; as the Lord had commanded Moses and Aaron, so they did.

29At midnight the Lord struck down all the firstborn in the land of Egypt, from the firstborn of Pharaoh who sat on his throne to the firstborn of the captive who was in the dungeon, and all the firstborn of the livestock.

30And Pharaoh rose up in the night, he and all his servants and all the Egyptians. And there was a great cry in Egypt, for there was not a house where someone was not dead.