There are five special prohibitions on Yom Kippur. We are forbidden to eat or drink, wear leather shoes, use makeup and lotions, bathe, and have marital relations. Therefore, it would appear that Yom Kippur is a solemn and non-festive day. However, Taanit 4:7 says that “Lo Hayu Yamim Tovim LeYisrael KeChamishah Asar BeAv VeYom HaKippurim.” Roughly translated, “Yom Kippur and the fifteenth of Av were the happiest days for Jews.” Furthermore, a mourner’s Shivah is canceled if Yom Kippur falls during the seven days of mourning. These seem to indicate that Yom Kippur is a joyous day. So is Yom Kippur a happy day or a solemn day?
The chief source for believing that Yom Kippur is not a joyous day is the word VeInitem from the words “VeInitem Et Nafshoteichem” (Vayikra 32:23), meaning that one should torture himself on Yom Kippur. However, as Rabbi Shlomo Riskin points out, there is another meaning of VeInitem. In Sefer Devarim, Moshe says (Devarim 26:5), “VeAnita VeAmarta Lifnei Hashem Elokecha,” which Chazal interpret as “You should sing out [i.e. sing with the cantillation tune) in front of Hashem, your God.” If we apply this meaning to the Pasuk about Yom Kippur, we find that it is a day to sing out to Hashem and reach our spiritual potential.
One might suggest that both meanings classify Yom Kippur; it is both a happy and a solemn day. While it is still one of the Asseret Yemei Teshuvah, and therefore warrants a serious attitude, Yom Kippur also represents the gift of a clean slate for all of Bnei Yisrael. Therefore, while we should certainly not ignore the serious implications and feeling of Yom Kippur, one should combine it with an optimism that takes into account Yom Kippur’s status as a new beginning for Bnei Yisrael.