The Succot that we build are to remind us of the ענני הכבוד, the Clouds of Glory of the desert. These clouds were in the merit of Aharon, and were a symbol of Hashem’s constant protection.
By leaving our comfortable homes and moving into the temporary dwelling, known as the Succah, we confirm that we understand how tentative life really is.
We must never forget for a moment, how we are not in control of our destiny. Our free will allows us to decide the direction we want to take in life. However, whatever transpired after this, is out of our control.
When we asked for forgiveness for the sin of תמהון לבב, confusion of the heart, on Yom Kippur, it refers to this very idea. This is generally understood to mean that we have not seen the hand of Hashem in everyday events.
We may have allowed ourselves to think that there are “coincidences.” Rabbi Avraham Twerski wrote that the definition of a coincidence is a miracle where G-d chose to remain anonymous.
The time we spend in the Succah should be on reflecting on our own vulnerabilities. This realization is to our benefit, as it allows us to get closer to Hashem, and feel His protection.
In the desert, the Clouds of Glory, were an obvious manifestation of Divine protection. The Succah is meant to remind us of this protection, and our total dependence on G-d.