R' Nachman writes that every Jewish soul is connected with the 70 holy souls that went down to Mitzrayim with Yaakov Avinu, which correspond to the 70 facets of the Torah. And on the side of impurity are the 70 nations of the world, with each nation representing another evil trait or worldly desire. And the desire for sexual transgression is the all-encompassing trait that represents all 70 evil traits and desires. And then R' Nachman writes, that he who succeeds in conquering this desire will find all the other desires of the world easy to conquer, and he will be worthy of having the secrets of the Torah revealed to him. (Lekutei Maharan, 36)