It is a mitzva to be in good spirits for the duration of the festival. At first glance, this would seem to be an easy mitzva, since everybody wants to be happy. However, in practice this mitzva is difficult to observe, because ever-present worries and tensions work against one’s happiness. Even so, this is the mitzva incumbent upon us during the festivals. We must transcend our worries and concerns, overcome our disappointments, and rejoice with God. To do so, we must remember that God chose us from among all the nations, gave us His Torah, sanctified us with His mitzvot, and brought us to the good land so that we could merit full and good lives – lives that have value and sanctity, and that can elevate the entire world and endow it with blessing and guidance until the world is completely redeemed. We will thus consider the great mission with which each of us is tasked. We remember all the good things in our lives. We strengthen our faith and recognize that all the hardships and exiles in Jewish history have had a positive purpose – to refine us, elevate us, and bring us closer to achieving our ultimate purpose. These meditations put us in a joyous mood throughout the festival.
There is no complete simḥa unless both body and soul are involved. Therefore, the festival mitzva of simḥa includes physical enjoyment – eating, drinking, and wearing nice clothes – as well as spiritual enjoyment – studying Torah and reciting the festive prayers.
On the festival, everyone must avoid whatever worries or saddens him. Additionally, he should not lose his temper or get angry. There are people who do not know how to enjoy spending time with their family. At every family gathering, they find a reason to cause a fight, bring up old grudges, and make their relatives miserable. This is all because they do not understand the great sanctity of the festival. Their festival observances are all performed by rote, devoid of spiritual content. As we have seen (section 11), these people should focus on the values and holiness of the festival, and this will help them become happier. They will avoid criticizing family members and keep away from remarks that are likely to be painful. Instead, they will try to compliment their family members and whoever else they meet. They will thus be able to enjoy themselves and bring joy to others during the festivals; these blessings will spill over into the weekdays as well.
Since it is a Torah commandment to be happy on Yom Tov and Ḥol Ha-mo’ed, one may not engage then in sad activities, even if the sadness is connected to a mitzva. Thus one may not fast for penitential purposes on a festival, and may not eulogize or lament the dead (MK 27a; SA 547:1-2). If the deceased is a Torah scholar, he is eulogized before the burial, because the honor due the Torah supersedes the holiday (MK 27b; SA YD 401:1; below 11:5; Harḥavot).
Similarly, it is forbidden to mourn on a festival. If someone dies before the festival, the mourning period ends with the start of the festival. Even if the mourner had a chance to mourn for only one moment, the mourning period ends once the festival begins (MK 14b; SA 548:7). In contrast, if one dies during the festival, the mourning period begins after the festival. During the festival, the mourner should do his best not to cry or be sad. He should rather occupy himself with the festival and its mitzvot (SA 548:1). If it is Sukkot, he is not exempt from the mitzva of sukka even if he is sad. He must overcome his anguish and sit in the sukka (Sukka 25a; SA 640:5). At the same time, even though he is not yet sitting shiva, his friends and relatives may come to comfort him (SA 548:6).