Tanya Chapter 31 part 4

Dedicating life to reuniting the soul with Hashem is a source of incredible happiness. And the joy grows greater still! Aside from the soul being restored to its former unity with Hashem through Torah and Mitzvos, there is something original in this life's journey that the soul didn't experience before. It is the unique opportunity to satisfy the Divine purpose in creation. When we realize what we accomplish in bringing our body and animal soul along in our holy pursuits, our lifelong teshuva gains even greater depth and intensified joy.