Exodus 12:27
you are to reply, 'It is the Passover sacrifice to the LORD, who passed over the houses of the Israelites in Egypt when He struck down the Egyptians and spared our homes.'" Then the people bowed down and worshiped.

Exodus 12:29
Now at midnight the LORD struck down every firstborn male in the land of Egypt, from the firstborn of Pharaoh, who sat on his throne, to the firstborn of the prisoner in the dungeon, as well as all the firstborn among the livestock.