Exodus 12:14; Exodus 12:15

14 "This day shall be for you a memorial day, and you shall keep it as a feast to the LORD; throughout your generations, as a statute forever, you shall keep it as a feast.

15 Seven days you shall eat unleavened bread. On the first day you shall remove leaven out of your houses, for if anyone eats what is leavened, from the first day until the seventh day, that person shall be cut off from Israel.