Exodus 12:15-17

15You must eat unleavened bread for seven days. On the first day you must remove yeast from your houses. Whoever eats what is leavened from the first day through the seventh day must be cut off from Israel.

16You are to hold a sacred assembly on the first day and another sacred assembly on the seventh day. No work may be done on those days except for preparing what people need to eat — you may do only that.

17“You are to observe the Festival of Unleavened Bread because on this very day I brought your military divisions out of the land of Egypt. You must observe this day throughout your generations as a permanent statute.