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.

Exodus 12:39

12:39 They baked cakes of bread without yeast using the dough they had brought from Egypt, for it was made without yeast – because they were thrust out of Egypt and were not able to delay, they could not prepare food for themselves either.

Exodus 23:15

23:15 You are to observe the Feast of Unleavened Bread; seven days you must eat bread made without yeast, as I commanded you, at the appointed time of the month of Abib, for at that time you came out of Egypt. No one may appear before me empty-handed.