Deuteronomy 16:3-8

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. 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. Thou mayest not sacrifice the passover within any of thy gates, which Jehovah thy God giveth thee; but at the place which Jehovah thy God shall choose, to cause his name to dwell in, there thou shalt sacrifice the passover at even, at the going down of the sun, at the season that thou camest forth out of Egypt. And thou shalt roast and eat it in the place which Jehovah thy God shall choose: and thou shalt turn in the morning, and go unto thy tents. Six days thou shalt eat unleavened bread; and on the seventh day shall be a solemn assembly to Jehovah thy God; thou shalt do no work therein.