Deuteronomy 16:2-4

American Standard Version

² And thou shalt sacrifice the passover unto Jehovah thy God, of the flock and the herd, in the place which Jehovah shall choose, to cause his name to dwell there. ³ Thou shalt eat no leavened bread with it; seven days shalt thou eat unleavened bread therewith, even the bread of affliction; for thou camest forth out of the land of Egypt in haste: that thou mayest remember the day when thou camest forth out of the land of Egypt all the days of thy life. ⁴ And there shall be no leaven seen with thee in all thy borders seven days; neither shall any of the flesh, which thou sacrificest the first day at even, remain all night until the morning.