Exodus 13:6

4Today you go out in the month Abib.

5It shall be, when the LORD brings you into the land of the Canaanite, and the Hittite, and the Amorite, and the Hivite, and the Jebusite, which he swore to your fathers to give you, a land flowing with milk and honey, that you shall keep this service in this month.

6Seven days you shall eat unleavened bread, and in the seventh day shall be a feast to the LORD.

7Unleavened bread shall be eaten throughout the seven days; and no leavened bread shall be seen with you. No yeast shall be seen with you, within all your borders.

8You shall tell your son in that day, saying, ‘It is because of that which the LORD did for me when I came out of Egypt.’