Every yom tov has its unique halachos and themes, and yet there are some aspects of yom tov that apply to all yomim tovim.
The bringing of Korbanos, referenced in Parshas Emor, plays a major role in the celebration of all yomim tovim. The Shalosh Regalim have their mitzvos of offering multiple Korbanos upon visiting the Beis Hamikdash, Yom Kippur has its unique Avodah that plays such a prominent role in the observance of the day, and even Rosh Hashana, which is not linked directly to the Mikdash, is observed in a unique way in the Beis Hamikdash. Teikas Shofar is performed slightly differently in the Beis Hamikdash; according to the Talmud Yerushalmi the practice of blowing Shofar on Shabbos only in the Beis Hamikdash is of Torah origin, thereby highlighting that Tekias Shofar in Mikdash is different than everywhere else. Furthermore, we can see from the fact that Elkanah and his family would visit the Mishkan in Shilo annually on Rosh Hashana that Rosh Hashana in Mikdash is unique.
In Parshas Re'eh we are instructed to be b'simcha (to rejoice) on the Shalosh Regalim. Although different from the Shalosh Regalim, the Yomim Noraim, according to many, are also times of joy. The Rambam notes that Rosh Hashana and Yom Kippur are not days of boundless joy because of the somber mood that must accompany days of judgment, nevertheless there, is to a lesser degree, a mitzva of rejoicing even on these days. The halacha that aveilus is cancelled by Rosh Hashana and Yom Kippur just as it is by the Shalosh Regalim proves that we have a chiyuv simcha even on the Yomim Noraim.
Our responsibility to do chessed with others, particularly those in dire need, has added significance on all of the yomim tovim. The Torah stresses that our joy cannot be complete without sharing with the poor and others who are in need financially or emotionally. In Parshas Emor we read that the celebration of the Shavuos harvest is only complete when we share of that harvest with others. It is not coincidental that the story of Megillas Rus is read on Shavuos; care for the needy is integral to celebration of the day. During the days of Ezra there was a great celebration of Rosh Hashana that is described in Tanach. We read not only of the Torah and Tefilla that marked the day but also of the sending of food to those in need. Rosh Hashana is not complete without caring for others. Although Yom Kippur does not involve providing food for the poor for Yom Kippur itself, the age-old custom of kapparos being distributed to the poor highlights that even Yom Kippur cannot be observed properly without caring for the needy.
These three universal aspects of yom tov - Mikdash, simcha, and chessed - are strongly linked to one another, and it is our connection to Hashem through the vehicle of Mikdash that sets the stage for the proper observance of yom tov.
As we visit Hashem's home and we experience being in His presence we are immediately filled with intense joy; Rabbi Soloveichik observed that the very mitzva of simcha is a direct result of being in Hashem's presence. The starting point of our very existence is a state of total joy, but as we drift further from Hashem our joy is mitigated. When we return, through aliyah l'regel on the Shalosh Regalim and through teshuva during the Yomim Noraim, we are filled again with that all-encompassing joy.
It is this simcha of reconnecting with Hashem through Mikdash that is the engine that drives our responsibility to others. The Ramban in his introduction to Vayikra highlights how the world of korbanos teaches us about the great kindness Hashem bestows on us. Korbanos which atone for our shortcomings are a gift from Hashem who is all compassionate. Rather than judging us strictly, He treats us with loving kindness. When we are recipients of His kindness, we in turn realize we must share that kindness with others. The Rambam (Hilchos Megilla) describes the significance of sharing the joy of Purim with those who need it most, telling us that one who does so is compared to Hashem Who acts in this manner and thus the sharing of joy with others is the greatest form of simcha.
May we merit to see the Beis Hamikdash rebuilt and our simcha complete as we share our joy with others and by doing so emulate Hashem Himself.
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