The Torah commands in Parashat Re’eh (Debarim 16:14), “Ve’samahta Be’hagecha” – that we must rejoice on the Yamim Tobim (festivals).
The primary form of rejoicing to which the Torah refers in this context is the offering of Shelamim sacrifices in the Bet Ha’mikdash and partaking of their meat, together with wine. However, the Sefer Ha’hinuch writes, this Misva is fulfilled also in other ways – such as by wearing new, fine clothing, and by giving family members treats. The Sefer Ha’hinuch adds that music, too, is a form of enjoyment through which this Misva is fulfilled. Of course, playing music is forbidden on Yom Tob, but it is allowed on Yom Tob in the Bet Ha’mikdash. Moreover, the Sefer Ha’hinuch emphasizes, one cannot fully experience Simha (rejoicing) on Yom Tob without assisting the poor, the downtrodden, and all those in need of help and support.
Explaining the reason behind this Misva, the Sefer Ha’hinuch writes that joy and festivity are among the basic needs of human beings. In addition to the need to eat and sleep, we also have a need to experience enjoyment, to indulge in delights on occasion. However, enjoyment and indulgence have a tendency to lead a person to improper, sinful behavior. Therefore, Hashem commanded us to celebrate special occasions, and enjoy festivity, in the context of a Misva, as part of a religious observance. This allows us to fill our need for enjoyment and festivity while helping to ensure that we conduct ourselves properly.
This Misva applies in all places and in all time eriods, and is binding upon both men and women. Of course, we cannot fulfill this obligation nowadays through the offering of sacrifices, but we observe this Misva through the consumption of regular meat, drinking wine, and other means of enjoyment.
Somebody who fails to rejoice on Yom Tob has neglected this Misvat Aseh (affirmative command).
The Sefer Ha’hinuch concludes his discussion of this Misva by citing the famous Rabbinic dictum, “Ve’chol Ma’asecha Yiheyu Le’shem Shamayim” – “All your actions shall be done for the sake of Heaven.” When we feast and rejoice on Yom Tob, we must direct our thoughts and attention to Hashem, and enjoy the holiday for His sake, and not purely for the sake of vain pleasure.