Deuteronomy 16:3-4

Leeser(i) 3 Thou shalt not eat therewith any leavened bread: seven days shalt thou eat therewith unleavened bread, the bread of affliction; for in haste didst thou go forth out of the land of Egypt; in order that thou mayest remember the day of thy going forth out of the land of Egypt all the days of thy life. 4 And there shall not be seen with thee any leaven in all thy borders seven days: neither shall there any of the flesh, which thou sacrificedst in the evening, on the first day, remain all night until the morning.