Deuteronomy 16:7 KJV

5Thou mayest not sacrifice the passover within any of thy gates, which the LORD thy God giveth thee:

6But at the place which the LORD thy God shall choose to place his name in, there thou shalt sacrifice the passover at even, at the going down of the sun, at the season that thou camest forth out of Egypt.

7And thou shalt roast and eat it in the place which the LORD thy God shall choose: and thou shalt turn in the morning, and go unto thy tents.

8Six days thou shalt eat unleavened bread: and on the seventh day shall be a solemn assembly to the LORD thy God: thou shalt do no work therein.

9Seven weeks shalt thou number unto thee: begin to number the seven weeks from such time as thou beginnest to put the sickle to the corn.