The cycle of Rosh HaShana, Yom Kippur, and Sukkot is a process of entering limits and emerging from them.
Rosh HaShana is the stern judgment by which the world must be measured and for which it must prepare.
Yom Kippur is the day of transition; on the one hand, the essence of the day is purification, pardoning of sin, and beginning a new period, yet on the other hand, Yom Kippur itself is a serious day of introversion.
In contrast, the Festival of Sukkot brings the joy of liberation.
Sukkot is the culmination of the process, of the emergence from narrow straits to broad expanses, from the limits of judgment to the expanse of compassion and love.
–Rabbi Adin Steinsaltz