Exodus 12:28

24You shall observe this thing for an ordinance to you and to your sons forever.

25It shall happen when you have come to the land which the LORD will give you, as he has promised, that you shall keep this service.

26It will happen, when your children ask you, ‘What do you mean by this service?’

27that you shall say, ‘It is the sacrifice of the LORD’s Passover, who passed over the houses of the children of Israel in Egypt, when he struck the Egyptians, and spared our houses.’” The people bowed their heads and worshiped.

28The children of Israel went and did so; as the LORD had commanded Moses and Aaron, so they did.

29At midnight, the LORD struck 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 livestock.

30Pharaoh 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 there was not one dead.

31He called for Moses and Aaron by night, and said, “Rise up, get out from among my people, both you and the children of Israel; and go, serve the LORD, as you have said!

32Take both your flocks and your herds, as you have said, and be gone; and bless me also!”