Deuteronomy 16:5-9

You are not allowed to sacrifice the Passover in any of your towns which the Lord your God is giving you;

but only at the place where the Lord your God chooses to establish His name, you shall sacrifice the Passover in the evening at sunset, at the time that you came out of Egypt.

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.

For six days you shall eat unleavened bread, and on the seventh day there shall be a festive assembly to the Lord your God; you shall do no work on it.

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