Exodus 12:29-30

²⁹It happened at midnight, that Yahweh 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 cattle. 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.