One of the eternal and ever-recurring theological questions asks why the neshama (the soul) descends to this world.
After all, the neshama is pure even before its descent, and it is implausible to contend that after the descent, after investing the effort and taking such a risk, it should return to the same level of purity that it once possessed, even in the best case scenario!
In this regard, one tzaddik (Rabbi Menahem Mendel of Kotzk) said: People think that man was created in order to rectify the soul.
The purpose for which man was created is to uplift the heavens.
The neshama does not descend to this world merely to return just as it came.
Rather, it descends so as to attain after the descent a level higher than it possessed before.
–Rabbi Adin Steinsaltz