Exodus 8:29

8:29 Moses said, “I am going to go out from you and pray to the Lord, and the swarms of flies will go away from Pharaoh, from his servants, and from his people tomorrow. Only do not let Pharaoh deal falsely again by not releasing the people to sacrifice to the Lord.”

Exodus 12:15

12:15 For seven days you must eat bread made without yeast. Surely on the first day you must put away yeast from your houses because anyone who eats bread made with yeast from the first day to the seventh day will be cut off from Israel.