Our Sages inform us1 that those spiritual matters that are in a state of concealment during Rosh HaShanah and Yom Kippur are revealed during the festival of Sukkos.

Rosh HaShanah and Yom Kippur each possess three distinct aspects, one greater than the other:2

a) The unique mitzvos of these days — on Rosh HaShanah the sounding of the shofar, and on Yom Kippur the mitzvos of fasting, repentance and confession.

b) The fact that both Rosh HaShanah and Yom Kippur are part of the Ten Days of Repentance, with penitence — capable as it is to atone for the non-performance and transgression of mitzvos — transcending mitzvos.

c) The essential quality of these days — on Rosh HaShanah, the aspect of accepting G‑d as King, and on Yom Kippur, the idea that “The very day [of Yom Kippur] brings atonement”3 — a degree of atonement that far surpasses the atonement that is achieved through teshuvah, repentance.

Although these three aspects are part of both Rosh HaShanah and Yom Kippur, in a more general sense each aspect is tied to one of the three primary festivals of the month of Tishrei: Rosh HaShanah, Yom Kippur and Sukkos.

Rosh HaShanah (“rosh” in Hebrew meaning “head”) clearly manifests its role as “head” of the year; it is the time when the Jewish people crownG‑d as King. This ability of the Jewish people to crown G‑d as King also indicates the Jews’ absolute unity with Him, a union so profound that it is able to bring about within G‑d the desire to reign.

Yom Kippur, the “Day of Forgiveness,” when “The very day brings atonement,” plainly displays that it is a day on which forgiveness is granted for transgressing the King’s decrees. This, too, is indicative of an essential union between G‑d and the Jewish people — a union that transcends obeying or disobeying His decrees.

The festival of Sukkos is the occasion when Jews are absorbed in G‑dliness and unite with G‑d through the performance of mitzvossukkah, esrog and lulav, etc. Indeed, the performance of mitzvos is indicated by the name of the holiday itself — Sukkos.

As mentioned above, all aspects that are concealed on Rosh HaShanah and Yom Kippur are revealed during Sukkos. Therefore, although the main feature of Sukkos is the performance of mitzvos, the festival also reveals the themes of Rosh HaShanah and Yom Kippur.

How does this revelation come about?

In describing the Sukkos festival, the Torah states: “On the fifteenth day of this seventh month is the Festival of Sukkos....”4 And with regard to dwelling in the sukkah the verse states: “You shall dwell in sukkos for seven days.”5 As nothing other than the mitzvah of sukkah is cited as the reason for the festival, clearly the essential feature is the sukkah itself.

With regard to the mitzvah of esrog and lulav, the verse states:6 “You shall take for yourselves [the esrog and lulov] on the first day[of Sukkos].” Since the first day of Sukkos in no way depends on taking the esrog and lulav but on dwelling in the sukkah, it follows that the mitzvah of esrog and lulav is not the essential aspect of the first day of Sukkos, it merely is a commandment to be performed on the first of Sukkos.

After the Torah commands taking the esrog and lulav, it goes on to say:7 “and you shall rejoice before the L‑rd your G‑d for seven days.” In other words, the commandment to rejoice during Sukkos is the third aspect of the festival, following the commandments of sukkah and taking the esrog and lulav.

Herein lies the connection between the three themes of Rosh HaShanah and Yom Kippur and their revelation within the festival of Sukkos:

a) The essential connection between Jews and G‑d — a relationship wherein all Jews are equal, and which is expressed in accepting G‑d’s Kingship on Rosh HaShanah — is revealed within the essential aspect of Sukkos; a unity that finds expression in the fact that “All Jews are fit to dwell in the selfsame sukkah.”8

b) Every Jew’s bond with G‑d (although not as intrinsic and essential as the aspect of Rosh HaShanah) is expressed through teshuvah — the main aspect of Yom Kippur — and manifests itself through the second Sukkos command of esrog and lulav, as the lulav serves as a symbol that Jews were victorious in atonement on Yom Kippur.9

c) Finally, the connection of the Jew to G‑d through the performance of mitzvos is revealed in the mitzvah of rejoicing on Sukkos — the cause of their rejoicing being the privilege of performing G‑d’s commands.

Based on Likkutei Sichos, Vol. XIX, pp. 350-354.