The Ari, z"l, mentions that, as we may know, the minimum requirement for building a Sukkah, is 2 walls and a bit, which is actually hinted in the letter ה (Heh) of Sukkah (סוכה). The word Sukkah, itself, hints to the different possibilities of what a kosher Sukkah is. The Simmakh (ס) tells us you can have 4 walls, since it is fully enclosed. The Kaf (כ) alludes to the fact that you can have 3 walls, since it is open on one side. The letter Heh (ה) which is only complete on two sides, plus part of a third, lets us know that the minimum number of walls which still renders a Sukkah valid, is two and a bit.
The Ari, z"l, tells us that this minimum requirement of 2 walls and a bit should remind us of the closeness that we can reach with הקדוש ברוך הוא, the Holy One blessed be He. One wall can be considered to be the upper part of the arm. The second wall is the lower part of the arm, and the small piece is actually the hand or the palm of the hand. We should feel how הקדוש ברוך הוא actually hugs us.
We are very close to Him, and we can reach this closeness only when we are at the level of spirituality that we have reached right now. Yom Kippur is only a few days behind us, and we are all busy now preparing for Sukkoth. We are running around getting the Arba' Minim (four species) and spending time decorating the Sukkah. This is now the peak of our spiritual attainment.
The Sukkah, unlike a house, is a temporary dwelling place. It’s not like a home that is steady, strong, and that can protect us from strong winds, storms, or snow. Sometimes, when people go through hard times in life, they ask, " Where are you G-d?" However, it is exactly at times when we feel that things are shaky, that we are not protected by our homes, that there isn’t a very powerful, solid foundation, when things are difficult, and there are challenges, that we have the greatest ability to become close to הקדוש ברוך הוא. This is the time when we must take advantage of our situation.
It says in the Tanakh : אין עוד מלבדו (there is none other than G-d). It may be paradoxical to our logical thinking. We think that we are much safer and protected when we’re inside a solid, good home. But the Sukkah gives us the exact opposite message. If you go through tests and challenges, you can feel safe, provided that you remember who runs the world. You can feel the strongest during these difficult moments provided that you remember that it’s not the four walls of your castle that protect you. We must remember that it is the Holy One blessed be He who hugs us and gives us the protection אין עוד מלבדו.