What is life? An enjoyment of the world, an exploitation of it, or an experience that never ends? Sukkot speaks to these questions, and speaks to the highest level of existence man can reach: to bask in the glory of G-d.
One can only benefit from divine splendor after they fix themselves to the highest degree. The fixing began on Rosh Hashanah, the near completion happens on Yom Kippur, and the basking in the shade occurs on Sukkot. Because man will always fail, as one Rav said, the key is to make our will G-d's Will.
Merciful Shade
There are very few mitzvo where you must have kavana on the purpose of the mitzvah. However, when saying Kiddush on the first night of Sukkot, we must know that the Sukkah commemorates the Ananei HaKavod, Clouds of Glory. Why such a requirement?
First, we must ask a fundamental question. If Yom Kippur is over, why do we still say LeDavid Hashem Ori throughout Sukkot? This seems to be a prayer more suited for Rosh Hashanah and Yom Kippur. It's where we are seeking repentance and hoping for mercy from our Shepherd.
That's really the point. In this same psalm (27:5) we say, “Yitzpenni bsucko - hide me in your shelter,” a remez to the Sukkah.
G-d's continuation of mercy is our shelter.
We are given time to reach the level necessary to bask in G-d"s splendor. We wish each other “a "good kvitel" up until Hoshanah Rabbah, where then the judgment is sealed.
Furthermore, every Shabbos permeates with the light of teshuva, giving man the continuous ability to reform his ways.
This can give meaning to the gematria, numerical value, of the word tzel, shade, which equals 120. The shade of the Sukkah brings man to his ultimate reach in this world, as it's fusing with the glory of G-d.
Rabbi Twerski's new book, Let Us Make Man, is the quintessential read that captures this “Sukkot Sentiment,” that man can fail but can't excuse his expected greatness. He was made by the Hand of G-d and must build himself up to a level where he can benefit from the aura of G-d.
A Determining Sun
Though the world can't exist on strict justice, justice will be served in the end. The shade of the Sukkah will at one point have to give way to the rays of sun.
The Gemara in Nedarim (8b) says that at the end of days G-d will remove the sun from its protective covering, and the tzaddikim will bask in it and the reshaim destroyed by it. The same element will bring opposite results, depending on one's station in life.
Yalkur Shimoni (653) also brings verses of how the reshaim will be consumed by fire, and we know this phenomenon happens in an instant when the final Messianic time has come.
Further it notes how when the enemies will come to fight in the land of Israel, G-d will act as a covering (Sukkah) over Bnei Yisrael on this “yom neshek,” day of battle.
Conclusion
This week the world is full of Sukkahs, temporary shelters imbued with G-d's glory. The Sukkah is temporary just like our stay in this world, but a permanent fixture to deliver mitzvot to the next world.
Based on G-d's mercy of accepting our best selves we can bask in the Shechinah.
G-d shelters us from our enemies, like a dwelling where we find ourselves covered, and fights our battles with His mightiness.