Deuteronomy 16:3

16:3 You must not eat any yeast with it; for seven days you must eat bread made without yeast, symbolic of affliction, for you came out of Egypt hurriedly. You must do this so you will remember for the rest of your life the day you came out of the land of Egypt.

Deuteronomy 16:12

16:12 Furthermore, remember that you were a slave in Egypt, and so be careful to observe these statutes.