Deut. 15: 9 You shall count off seven weeks; start to count the seven weeks when the sickle is first put to the standing grain. 10 Then you shall observe the Feast of Weeks for the Lord your God, offering your freewill contribution according as the Lord your God has blessed you. 11 You shall rejoice before the Lord your God with your son and daughter, your male and female slave, the Levite in your communities, and the stranger, the fatherless, and the widow in your midst, at the place where the Lord your God will choose to establish His name. 12 Bear in mind that you were slaves in Egypt, and take care to obey these laws.

13 After the ingathering from your threshing floor and your vat, you shall hold the Feast of Booths for seven days. 14 You shall rejoice in your festival, with your son and daughter, your male and female slave, the Levite, the stranger, the fatherless, and the widow in your communities. 15 You shall hold a festival for the Lord your God seven days, in the place that the Lord will choose; for the Lord your God will bless all your crops and all your undertakings, and you shall have nothing but joy.

Darby Bible Translation
Seven days shalt thou hold a feast to Jehovah thy God in the place which Jehovah will choose; for Jehovah thy God will bless thee in all thy produce, and in all the work of thy hands, and thou shalt be wholly joyful.

Deuteronomy 16:15 Seven days you will celebrate the festival+ to Jehovah your God in the place that Jehovah will choose, because Jehovah your God will bless+ you in all your produce and in every deed of your hand, and you must become nothing but joyful.+

Doesn't Hava Nagila song refer to above?^

ps.118:155 The voice of rejoicing and salvation
Is in the tents of the righteous;

New International Version (©1984)
Sarah said, "God has brought me laughter, and everyone who hears about this will laugh with me."

Isaac means "to laugh"