Exodus 12:13-15

13But the blood on your houses will be a sign for your protection. When I see the blood, I will pass over you. Nothing will touch or destroy you when I strike Egypt.

14“This day will be one for you to remember. This is a permanent law for generations to come: You will celebrate this day as a pilgrimage festival in the Lord’s honor.

15For seven days you must eat unleavened bread. On the very first day you must remove any yeast that you have in your houses. Whoever eats anything with yeast in it from the first day through the seventh day must be excluded from Israel.