Exodus 13:5-7

5You must celebrate this event in this month each year after the Lord brings you into the land of the Canaanites, Hittites, Amorites, Hivites, and Jebusites. (He swore to your ancestors that he would give you this land—a land flowing with milk and honey.)

6For seven days the bread you eat must be made without yeast. Then on the seventh day, celebrate a feast to the Lord.

7Eat bread without yeast during those seven days. In fact, there must be no yeast bread or any yeast at all found within the borders of your land during this time.