Exodus 34:25 "You shall not offer the blood of My sacrifice with leavened bread, nor is the sacrifice of the Feast of the Passover to be left over until morning.

Numbers 9:11 'In the second month on the fourteenth day at twilight, they shall observe it; they shall eat it with unleavened bread and bitter herbs.

Numbers 9:12 'They shall leave none of it until morning, nor break a bone of it; according to all the statute of the Passover they shall observe it.

Deuteronomy 16:3 "You shall not eat leavened bread with it; seven days you shall eat with it unleavened bread, the bread of affliction (for you came out of the land of Egypt in haste), so that you may remember all the days of your life the day when you came out of the land of Egypt.

Deuteronomy 16:4 "For seven days no leaven shall be seen with you in all your territory, and none of the flesh which you sacrifice on the evening of the first day shall remain overnight until morning.

Deuteronomy 16:7 "You shall cook and eat it in the place which the LORD your God chooses. In the morning you are to return to your tents.

1 Corinthians 5:8 Therefore let us celebrate the feast, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth. (NASB ©1995)