Exodus 12:28-30

28And the children of Israel went away, and did as Jehovah had commanded Moses and Aaron; so did they.

29And it came to pass that at midnight Jehovah smote all the firstborn in the land of Egypt, from the firstborn of Pharaoh who sat on his throne to the firstborn of the captive that was in the dungeon, and all the firstborn of cattle.

30And Pharaoh rose up in the night, he, and all his bondmen, and all the Egyptians; and there was a great cry in Egypt; for there was not a house in which there was not one dead.