Exodus 12:15-17

15Seven days shall ye eat unleavened bread: on the very first day ye shall put away leaven out of your houses; for whoever eateth leavened bread from the first day until the seventh day — that soul shall be cut off from Israel.

16And on the first day ye shall have a holy convocation, and on the seventh day a holy convocation: no manner of work shall be done on them, save what is eaten by every person — that only shall be done by you.

17And ye shall keep the [feast of] unleavened [bread]; for in this same day have I brought your hosts out of the land of Egypt; and ye shall keep this day in your generations [as] an ordinance for ever.