Deuteronomy 16:2-3 You shall sacrifice the Passover [lamb] to the LORD your God from the flock or the herd, in the place where the LORD chooses to establish His Name (Presence). You shall not eat leavened bread with it; | Amplified Bible (AMP)

Deuteronomy 16:2-3 AMP

You shall sacrifice the Passover [lamb] to the LORD your God from the flock or the herd, in the place where the LORD chooses to establish His Name (Presence). You shall not eat 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.

Read Deuteronomy 16