“All of Israel can sit in one sukah.” All sukahs are connected. Each sukah is a cell, the cells unite to become one living, joyful organism.
On Rosh Hashanah we return to God in thought, Yom Kippur in word, and Sukot in deed. In preparation for the mitzvot of Sukot we give charity.
Charity, tzedakah, is the all-inclusive mitzvah (commandment, good deed). As the sukah to the lulav, it encompasses all the other mitzvot.
The essence of a mitzvah is the joy we experience when fulfilling the will of our Creator. Maimonides: the greatest joy is in giving charity.