Deuteronomy 16:4
Yeast is not to be seen in any of your territories for seven days. The meat is not to remain from the evening of the first day until morning.
Exodus 12:10
Don't leave any of it until morning, and whatever does remain of it until morning you are to burn in the fire.
Exodus 34:25
"You are not to offer the blood of my sacrifice with anything leavened, nor are you to allow the sacrifice of the Festival of Passover to remain until morning.
Exodus 13:7
Unleavened bread is to be eaten for seven days, and nothing leavened is to be seen among you, nor is leaven to be seen among you throughout your territory.
Exodus 12:15
You are to eat unleavened bread for seven days. On the first day be sure to remove all the leaven from your houses, because any person who eats anything leavened from the first day until the seventh will be cut off from Israel.
Exodus 12:8
That very night they're to eat the meat, roasted over the fire, with unleavened bread and bitter herbs.