Deuteronomy 16:5

1Observe the month of Abib, and keep the Passover to the LORD your God; for in the month of Abib the LORD your God brought you out of Egypt by night.

2You shall sacrifice the Passover to the LORD your God, of the flock and the herd, in the place which the LORD shall choose to cause his name to dwell there.

3You shall eat no leavened bread with it. You shall eat unleavened bread with it seven days, even the bread of affliction (for you came out of the land of Egypt in haste) that you may remember the day when you came out of the land of Egypt all the days of your life.

4No yeast shall be seen with you in all your borders seven days; neither shall any of the meat, which you sacrifice the first day at evening, remain all night until the morning.

5You may not sacrifice the Passover within any of your gates which the LORD your God gives you;

6but at the place which the LORD your God shall choose to cause his name to dwell in, there you shall sacrifice the Passover at evening, at the going down of the sun, at the season that you came out of Egypt.

7You shall roast and eat it in the place which the LORD your God chooses. In the morning you shall return to your tents.

8Six days you shall eat unleavened bread. On the seventh day shall be a solemn assembly to the LORD your God. You shall do no work.

9You shall count for yourselves seven weeks. From the time you begin to put the sickle to the standing grain you shall begin to count seven weeks.