Deuteronomy 16:3-8

You shall eat no leavened bread with it. Seven days you shall eat it with unleavened bread, the bread of affliction—for you came out of the land of Egypt in haste—that all the days of your life you may remember the day when you came out of the land of Egypt. No leaven shall be seen with you in all your territory for seven days, nor shall any of the flesh that you sacrifice on the evening of the first day remain all night until morning. You may not offer the Passover sacrifice within any of your towns that the LORD your God is giving you, but at the place that the LORD your God will choose, to make his name dwell in it, there you shall offer the Passover sacrifice, in the evening at sunset, at the time you came out of Egypt. And you shall cook it and eat it at the place that the LORD your God will choose. And in the morning you shall turn and go to your tents. For six days you shall eat unleavened bread, and on the seventh day there shall be a solemn assembly to the LORD your God. You shall do no work on it.