An adaptation of a traditional story, retold by Doug Lipman, used with permission.
Some students of the Rabbi Baal Shem Tov came to him one day with a question. "Every year we travel here to learn from you. Nothing could make us stop doing that. But we have learned of a man in our own town who claims to be a tzaddik, a learned and righteous one. If he is genuine, we would love to profit from his wisdom. But how will we know if he is a fake?"
The Baal Shem Tov looked at his earnest students. "You must test him by asking him a question." He paused. "You have had difficulty with stray thoughts during prayer?"
"Yes!" The students answered eagerly. "We try to think only of our holy intentions as we pray, but other thoughts come into our minds. We have tried many methods not to be troubled by them."
"Good," said the Baal Shem Tov. "Ask him the way to stop such thoughts from entering your minds." The Baal Shem Tov smiled. "If he has an answer, he is a fake."