Deuteronomy 16:13

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.

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.

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

You shall rejoice in your feast, you, your son, your daughter, your male servant, your female servant, the Levite, the foreigner, the fatherless, and the widow who are within your gates.

You shall keep a feast to the LORD your God seven days in the place which the LORD chooses, because the LORD your God will bless you in all your increase and in all the work of your hands, and you shall be altogether joyful.

Three times in a year all of your males shall appear before the LORD your God in the place which he chooses: in the feast of unleavened bread, in the feast of weeks, and in the feast of booths. They shall not appear before the LORD empty.