Exodus 12:17-19

New Revised Standard Version, Anglicised Catholic Edition

¹⁷ You shall observe the festival of unleavened bread, for on this very day I brought your companies out of the land of Egypt: you shall observe this day throughout your generations as a perpetual ordinance. ¹⁸ In the first month, from the evening of the fourteenth day until the evening of the twenty-first day, you shall eat unleavened bread. ¹⁹ For seven days no leaven shall be found in your houses; for whoever eats what is leavened shall be cut off from the congregation of Israel, whether an alien or a native of the land.