Exodus 12:13-15

13The blood will be a sign for you on the houses where you are. When I see the blood, I will pass over you. So there will be no plague among you to destroy you when I strike the land of Egypt.

14“This day is to be a memorial for you. You are to keep it as a feast to Adonai. Throughout your generations you are to keep it as an eternal ordinance.

15For seven days you are to eat matzot , but on the first day you must remove hametz from your houses, for whoever eats hametz from the first day until the seventh day, that soul will be cut off from Israel.