"And you shall rejoice on your festival"—Deuteronomy 16:14.
The primary element of this mitzvah is the obligation to bring a Peace Offering (in addition to the Chagigah Peace Offering), known as the Simchah Peace Offering.
Also included in this mitzvah is the obligation to rejoice in a variety of ways. This includes eating meat, drinking wine (which is a paramount obligation), wearing new clothing, giving fruits and sweets to the women and children, and the Simchat Beit Hashoevah ("the Celebration of the Water Drawing") in the Temple that featured music and dancing.
The Torah requires us to include in our rejoicing the needy, the poor and the converts.
This is one of the three mitzvot associated with the festivals; the other two are Pilgrimage and offering the Festival Offering.
