Exodus 12:15-20

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.

12:16 On the first day there will be a holy convocation, and on the seventh day there will be a holy convocation for you. You must do no work of any kind on them, only what every person will eat – that alone may be prepared for you. 12:17 So you will keep the Feast of Unleavened Bread, because on this very day I brought your regiments out from the land of Egypt, and so you must keep this day perpetually as a lasting ordinance. 12:18 In the first month, from the fourteenth day of the month, in the evening, you will eat bread made without yeast until the twenty-first day of the month in the evening. 12:19 For seven days yeast must not be found in your houses, for whoever eats what is made with yeast – that person will be cut off from the community of Israel, whether a foreigner or one born in the land. 12:20 You will not eat anything made with yeast; in all the places where you live you must eat bread made without yeast.’”

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.

Leviticus 23:8

23:8 You must present a gift to the Lord for seven days, and the seventh day is a holy assembly; you must not do any regular work.’”