Exodus 12:17

This day shall be a memorial for you. You shall keep it as a feast to the LORD. You shall keep it as a feast throughout your generations by an ordinance forever.

“‘Seven days you shall eat unleavened bread; even the first day you shall put away yeast out of your houses, for whoever eats leavened bread from the first day until the seventh day, that soul shall be cut off from Israel.

In the first day there shall be to you a holy convocation, and in the seventh day a holy convocation; no kind of work shall be done in them, except that which every man must eat, only that may be done by you.

In the first month, on the fourteenth day of the month at evening, you shall eat unleavened bread, until the twenty first day of the month at evening.

There shall be no yeast found in your houses for seven days, for whoever eats that which is leavened, that soul shall be cut off from the congregation of Israel, whether he is a foreigner, or one who is born in the land.

You shall eat nothing leavened. In all your habitations you shall eat unleavened bread.’”