In the Siftei Chachamim, Rav Friedlander explains how Kohelet shows what we should put our trust in. Kohelet (5:11) says, “VeHaSava LeAshir Ainenu Maniach Lo Lishon,” “A man’s riches keep him from sleeping.” This concept is also illustrated by a Mishnah in Avot 2:7, “Marbeh Nechasim Marbeh De’agah,” “The more possessions, one has, the more he worries.”
Rav Friedlander explains that a person’s possessions steal his ability to feel secure. First, they make him feel self-sufficient; next, he places his trust in his own possessions. Ultimately, his whole sense of security disappears because he is putting his trust in something that can be taken from him, and he worries all the time, unable to sleep for fear that he’ll be losing something. It is only when a person submits himself entirely to Hashem that he is then able to sleep and feel safe.
This idea is demonstrated in our building of Sukkot. At the end of the harvest season, we take ourselves from our permanent dwellings and place ourselves outside in temporary houses. We then put an unstable roof over our heads, giving us a sense of complete reliance on Hashem. It is at that point that we recognize that our successes do not come as a result of our “efforts.” The world does not operate based on “Kochi VeOtzem Yadi Assah Li Et HaChayil Hazeh,” “It is my [man’s] strength that has created this produce,” but instead on Hashem’s blessings that are bestowed upon us.
A reason Ashkenazim read Kohelet on Sukkot also stems from this idea. Much of Kohelet teaches that material things are not worth anything and that Hashem is the only Being we should be putting our faith in. This idea is even expressed in the penultimate Pasuk of Kohelet (12:13- when reading Kohelet in shul, this Pasuk is repeated after the final one in order to end on a positive note): “Sof Davar HaKol Nishma Et HaElokim Yerah VeEt Mitzvotav Shemor Ki Zeh Kol HaAdam,” “In conclusion, after all has been heard, fearing Hashem and keeping His commandments is man’s whole duty.”
We can feel secure as long as we put our complete faith in Hashem, and so doing we can be assured of His help.