A person needs to be an expert on how to go along the path of teshuva. According to Rebbe Nachman, this is called ratzo v'shov, running and returning.
A person can take something lofty upon himself. He runs headlong into it, thinking he is really getting close to God now... but his expectations extend far beyond his actual ability. When he fails to meet his own high expectations, he falls completely in frustration and despair, failing to even accomplish what is within his ability. This is the concept of ratzo, running.
When one comes crashing down from unrealistic expectations, a person is greatly weakened. This can happen even with normal expectations, when one sees that he has not reached them in the way he wanted. This is the meaning of being expert in Running and Returning. "I will run to it, but whatever I achieve, I will be happy with what I managed to achieve without being frustrated." Then renew your energies and try again with more realistic expectations. This is shov, returning.
The dynamic of ratzo v'shov can be expressed another way: When a person ascends so high in his spirituality and feels so close to God (ratzo, running), he needs to know that he is still far and has not attained God, as it were. On the other hand, the idea of shov, returning, is when a person is in the lowest of depths, feeling like nothing, thinking he will never get up again. The Yetzer HaRa says, "You should know yourself already. You will never change. You will just keep making the same mistakes over and over again. Why even try to get up?" It is here where God says, "I am with you in this place, let us ascend together."
These ideas are the secret of teshuva.
Taken from a recent shiur of Rav Ephraim Kenig, shlita, based on Likutey Moharan 6:4.

