The prodigious chossid, Rabbi Yitzchak Horowitz (Itche der Masmid) would often tell the following story to express the power of learning Chassidus:
In a certain town in Russia, there was a certain landowner who was exceptionally cruel. On his property he raised particularly vicious dogs who would attack anyone that approached the property.
Once, as a certain Jew was traveling next to the property in a wagon he noticed another Jew that was walking alongside the landowner’s property. The Jew that was in the wagon asked the Jew that was walking: “aren’t you afraid of the landowner’s vicious dogs?” to which the Jew that was walking responded, “No, I am not afraid, as I have a certain incantation that I recite and the dogs run away.”
After a few minutes the dogs started chasing the man that was walking. Suddenly, the man cried for help and attempted to board the wagon. After he had safely boarded the man asked him: “what happened to your incantation that you were so sure about?” to which the man responded: “the incantation works perfectly, the problem is that the dogs were running so quick that I had no time to say the incantation…”
The dog is the animal soul that attempts to attack a person and cause him to sin. The incantation is the study of Chassidus that protects the person. If a person sees that he is studying Chassidus and the animal soul still makes him fall in sin, it is not to say that the “incantation” does not work, rather, it works but the animal soul gets to him so quickly that he is unable to use it properly.