Deuteronomy 16:3-5

American Standard Version

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. ⁵ Thou mayest not sacrifice the passover within any of thy gates, which Jehovah thy God giveth thee;