Perhaps

There happened to be at that time a very learned man, a man who prided himself on his education, and who boasted of being enlightened. He made a practice of going from one rabbi to another, in order to debate with them about their faith, and refute the proofs of their claims, which he considered hopelessly old-fashioned.

Finally, one day, he came to Levi Yitzhak, the rabbi of Berdichev, with the same intent. When he entered his room, he saw the Rabbi walking up and down, a book in his hand, immersed in ecstatic thought. The rabbi took no notice of his visitor whatsoever. After a time, however, the rabbi stopped, gave the man a brief glance, and said, "But perhaps it is true after all!"

In vain did the learned man try to rally his self-confidence. His knees shook, for the Rabbi was terrible to behold and his simple words were terrible to hear. But now Rabbi Levi Yitzhak turned to him and calmly addressed him: "My son, the great Torah scholars whom you debated, wasted their words on you. When you left them you only laughed at what they had said. They could not set God and his Kingdom on the table before you, and I cannot do this either. But, my son, only think! Perhaps it is true. Perhaps it is true after all." The enlightened man made the utmost effort to reply, but the terrible "perhaps" beat on his ears again and again, and broke down his resistance.