Deuteronomy 16:5-9

16:5 You may not sacrifice the Passover in just any of your villages that the Lord your God is giving you, 16:6 but you must sacrifice it in the evening in the place where he chooses to locate his name, at sunset, the time of day you came out of Egypt. 16:7 You must cook and eat it in the place the Lord your God chooses; you may return the next morning to your tents. 16:8 You must eat bread made without yeast for six days. The seventh day you are to hold an assembly for the Lord your God; you must not do any work on that day.

The Festival of Weeks

16:9 You must count seven weeks; you must begin to count them from the time you begin to harvest the standing grain.