Exodus 13:3-8

So Moses said to the people, “This is a day to remember forever—the day you left Egypt, the place of your slavery. Today the LORD has brought you out by the power of his mighty hand. (Remember, eat no food containing yeast.) On this day in early spring, in the month of Abib, you have been set free. You 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.) For seven days the bread you eat must be made without yeast. Then on the seventh day, celebrate a feast to the LORD. Eat 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. “On the seventh day you must explain to your children, ‘I am celebrating what the LORD did for me when I left Egypt.’