Deuteronomy 16:3-5

Amplified Bible

³ You shall not eat ^[a]leavened bread with it; instead, for seven days you shall eat the Passover with unleavened bread, the bread of affliction (for you left the land of Egypt in haste); [do this] so that all the days of your life you may remember [thoughtfully] the day when you came out of the land of Egypt. ⁴ For seven days no leaven shall be seen with you in all your territory, and none of the meat which you sacrificed the evening of the first day shall remain overnight until morning. ⁵ You are not allowed to sacrifice the Passover [lamb] in any of your cities which the Lord your God is giving you;