Exodus 12:17-20

17You shall also observe 1the Feast of Unleavened Bread, for on this 2very day I brought your hosts out of the land of Egypt; therefore you shall observe this day throughout your generations as 3a 4permanent ordinance. 185In 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. 196Seven days there shall be no leaven found in your houses; for whoever eats what is leavened, that 78person shall be cut off from the congregation of Israel, whether he is an alien or a native of the land. 20You shall not eat anything leavened; in all your dwellings you shall eat unleavened bread.’”