Exodus 12:12-14

For I will pass through the land of Egypt this night, and will smite all the firstborn in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgment: I {am} the LORD. {gods: or, princes} And the blood shall be to you for a token upon the houses where ye {are}: and when I see the blood, I will pass over you, and the plague shall not be upon you to destroy {you}, when I smite the land of Egypt. {to destroy...: Heb. for a destruction} And this day shall be unto you for a memorial; and ye shall keep it a feast to the LORD throughout your generations; ye shall keep it a feast by an ordinance for ever.