Exodus 13:3

13:3 Moses said to the people, “Remember this day on which you came out from Egypt, from the place where you were enslaved, for the Lord brought you out of there with a mighty hand – and no bread made with yeast may be eaten.

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.

Exodus 34:18

34:18 “You must keep the Feast of Unleavened Bread. For seven days you must eat bread made without yeast, as I commanded you; do this at the appointed time of the month Abib, for in the month Abib you came out of Egypt.