Principle 16: Getting back up after a fall
If we experience a fall, we must never let it get us down. Getting depressed is exactly what the Yetzer Hara wants, and it leads to a vicious cycle of continued falls.
The truest test of an eved Hashem is davka when Hashem takes everything away from him, such as when he falls and feels no inspiration, no emotion and no Hislavus. That's the moment of truth where a person can ask himself honestly, “am I an eved Hashem because it's my nature and/or because it keeps me emotionally happy, or do I serve the Almighty because that's His will and nothing else?”
The Lechevitcher Rebbe (a student of R' Shlomo of Karlin) once went as far as to say that even if a person just killed someone and the knife is still dripping with blood, and he feels unable to stand up and daven Mincha (the afternoon service) with all his strength and heart, then he has not yet tasted from the waters of Chassidus!
The Be’er Mayim Chayim says that in the army, when they would want to test a great soldier to see if he's fit to be a general, they would put him on a wild horse that was impossible not be thrown off of. Although no one could stay on that horse, the test was only to see how fast he would get back up after he was brutally thrown down and wounded.