Deuteronomy 16:4
No leaven should be seen with you in all your territory for seven days. None of the flesh you sacrifice on the evening of the first day shall remain overnight until morning.
Exodus 12:10
Eat what you want that night, and the next morning burn whatever is left.
Exodus 34:25
Do not offer the blood of a sacrifice to me at the same time you offer anything containing yeast. No part of the sacrifice at the Passover festival should be left over in the morning.
Exodus 13:7
Unleavened bread shall be eaten seven days. No leavened bread shall be seen with you or in all your borders.
Exodus 12:15
You will eat unleavened bread for seven days. The first day you shall remove leaven from your houses. Whoever eats anything leavened from the first day until the seventh day will be cut off from Israel.
Exodus 12:8
That night the animals are to be roasted and eaten, together with bitter herbs (greens) and unleavened bread made without yeast.