Deuteronomy 16:7-9

Amplified Bible

⁷ You shall cook and eat it in the place which the Lord your God chooses. In the morning you are to return to your tents. ⁸ For six days you shall eat unleavened bread, and on the seventh day there shall be a celebration to the Lord your God; so you shall do no work [on that day].

The Feast of Weeks

⁹ “You shall count seven weeks for yourself; you shall begin to count seven weeks from the time you first put the sickle to the standing grain.