Deuteronomy 16:3-5

Revised Standard Version

³ You shall eat no leavened bread with it; seven days you shall eat it with unleavened bread, the bread of affliction—for you came out of the land of Egypt in hurried flight—that all the days of your life you may remember the day when you came out of the land of Egypt. ⁴ No leaven shall be seen with you in all your territory for seven days; nor shall any of the flesh which you sacrifice on the evening of the first day remain all night until morning. ⁵ You may not offer the passover sacrifice within any of your towns which the Lord your God gives you;