3. All Yomim Tovim (festivals) are called “festivals for rejoicing.” Sukkos however, has the unique distinction of being “the season of our rejoicing,” for there is greater joy on Sukkos than on other festivals. The reason for this is that Sukkos is the festival that immediately
follows Yom Kippur [the four intervening days being a time for preparation for Sukkos — to build a Sukkah, acquire a Lulav and Esrog etc.]. On Yom Kippur, Jews are sealed for a good and sweet year in both spiritual and physical matters. Sukkos, which follows immediately after, is the revelation and celebration of the blessings bestowed on us on Yom Kippur. The blessings for the entire
year, including the other festivals, stem from Yom Kippur; and since Sukkos is the celebration and revelation of these blessings, it follows that the joy of the other festivals stems from the joy and celebration on Sukkos. This then is the reason why Sukkos alone among the festivals is called the “season of our rejoicing.”
When Jews gather together on Sukkos, especially when some, or most of them, are guests, additional blessings are bestowed upon them. For our Sages have said: “Hospitality to guests is greater than welcoming the Divine Presence” — hospitality has a loftier effect than welcoming G-d Himself. For G-d derives great joy from Jews uniting together and loving each other in consonance with the command “Love your fellow as yourself” — to the extent that it finds concrete expression in simple hospitality. This effects blessings (additional to that bestowed on Yom Kippur and revealed on Sukkos) for a good and sweet year in all things.
Just as a Jew, because of his love for a fellow, gives of his own to a fellow Jew on Sukkos, so too, he gives from the good and sweet things he has received to a fellow Jew the entire year. This then effects additional blessings from G-d every day of the year, making it a good and sweet year, leading to the true good — the true and complete redemption through our righteous Mashiach.
The unity and peace between Jews even now, in exile, is the preparation to the coming of Mashiach, when he will take every Jew “with our youth, our elders, our sons and our daughters” to our Holy Land in the future redemption. Then, together with Mashiach, we will fulfill all the mitzvos, including those associated with Yom Tov — hospitality, and the dissemination of Judaism in general and Chassidus in particular. All these things however, we do even now, before the coming of our righteous Mashiach, with joy and a good heart.