The Ability to Rejoice
Our Rabbis tell us that the festival of Passover parallels the First Temple, Shavuos parallels the Second Temple, and Sukkos parallels the Third Temple to be built by Mashiach. For it is the ability to rejoice and celebrate in G-d's service, the theme which Sukkos teaches, which will characterize the Era of the Redemption.
The Sukkah of Peace
In our prayers, we praise G-d for "spreading over us [His] sukkah of peace."
In a like vein, our Sages explain that the happiness, satisfaction, and peace which we feel in our sukkahs is a reflection of the ultimate happiness, satisfaction, and peace , we will feel in the Era of the Redemption.
One Sukkah for All
There is a connection between the ultimate Redemption and the holiday of Sukkot. For at that time, we will benefit from the Sukka made from the skin of the giant fish, the Leviathan. In the Redemption, the oneness of the Jewish people -- a concept which is true at all times -- will be openly revealed and we will see how "all Jews are fit to dwell in a single Sukka."
(The Rebbe, 4th day of Sukkot, 5752)
The Festival of Gathering
Sukkot is referred to as Chag HaAssif -- the harvest festival. This name also relates to the Jews' gathering together with Ahavat Yisrael [love for one's fellow Jew]. Such gatherings precipitate the ultimate gathering of the Jewish people which will take place at the time of the Redemption. For when division and strife, the cause of the exile, are nullified, the exile itself, the effect, will be nullified.
(The Rebbe, Sukkot 5752-1992)
Moshiach Within Us
When the Ark is opened before the Torah reading on the festivals, we pray: "May there be realized in us the verse [describing Moshiach] which states, 'The spirit of G-d shall rest upon him, the spirit of wisdom and understanding, counsel and strength, knowledge and the fear of G-d.'"
Since within every Jew there is a spark of Moshiach, every Jew can ask that this verse be fulfilled with respect to the spark of Moshiach within his soul.
Thus, this prayer is appropriate for every Jew, regardless of his spiritual standing.
(The Rebbe, 5743)