This is an incredible yesod. A person is aware of his shortcomings—and davka because of this, he comes with his neshamah to daven, so he should access the light once again and become healed. Thus, the more a person is caught in the quagmire of his aveiros, the greater the power of his neshamah to return him to the Source. Sometimes, we find a person who’s stuck in a rut, and he is a cold person who’s hard to move... Even this person can be returned through tefillah. It is for everyone, in every matzav.
Rebbe Mordechai of Lechovitz has said that if a person committed the worst aveirah and cannot immediately stand up and daven to Hashem, he has not begun to grasp chassidus. Indeed, chassidus explained what the neshamah is and that the holiness of the neshamah is incorruptible. It can always return to its Source, no matter what.
