When the stranger entered the little shul, the regulars were curious -- who was he and why had he come to their town. But he was in a great hurry and so, he was relieved to see a quorum of men already assembled, ready to begin the morning prayers. There was no rabbi there, and not wanting to wait, the stranger ascended the bima. The "regulars" were surprised and offended that this unknown man presumed to lead the prayers. After all, who was this fellow, who didn't even have the courtesy to wait a few minutes for the rabbi or the president of the congregation?

The stranger had already begun the morning service when the president arrived. Seeing a stranger at the bima, he rushed up to him and said, "What a chutzpa! Who do you think you are to begin the prayers before the rabbi or I have arrived!" And he continued berating the man in this fashion.

The stranger, however, just kept silent. But his refusal to respond infuriated the president even more and he blurted out, "Don't you see who's speaking to you?"

Finally the stranger replied in a quiet voice, "You also do not see to whom you are speaking."

No sooner had those words been uttered than everything went dark before the president's eyes. He rushed to a doctor, then to a specialist -- to several specialists -- but no one could find a cause for his sudden blindness. He tried every treatment that was suggested to him, but nothing proved a cure.

Then, it dawned upon him: when had his blindness begun? After he had angry words with the stranger in the shul. Undoubtedly he had offended a hidden tzadik with his words, and this was the consequence of his anger.

In despair, he decided to travel to the Baal Shem Tov. He had heard about this great tzadik; maybe he could help.

"Rebbe, I have heard that you can perform miracles. I have been blind since I angered a certain hidden tzadik. My problem is that I don't know who he is or where I can find him."

The Baal Shem Tov replied, "The man is my disciple, Reb Yaakov Koppel, and you sinned against him with your angry speech. Go to him and beg his forgiveness. If he forgives you, your blindness will be cured."

The man indeed traveled to Reb Yaakov, who accepted his apology. His sight returned as quickly as it had vanished.