Deuteronomy 16:9

6 but 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.

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

8 Six 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.

9 You 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.

10 You shall keep the feast of weeks to the LORD your God with a tribute of a free will offering of your hand, which you shall give according to how the LORD your God blesses you.

11 You shall rejoice before the LORD your God: you, your son, your daughter, your male servant, your female servant, the Levite who is within your gates, the foreigner, the fatherless, and the widow who are among you, in the place which the LORD your God shall choose to cause his name to dwell there.

12 You shall remember that you were a slave in Egypt. You shall observe and do these statutes.