They say someone asked the Rebbe's wife what she thought of her husband. "I'll tell you one thing," she replied. "My husband believes in G‑d."

Great faith of a simple mind is not so impressive. Simple faith of a great mind is. Perhaps the simple person just hasn't asked the right questions. Perhaps faith is convenient for him. Perhaps he's afraid of what his wife might do to him if he came home one day and announced he no longer believes.

A truly great mind is not swayed by such concerns. Nothing forces him to believe —he believes because it is the truth. And since his faith is not self-serving, but founded on a truth beyond the self, therefore it is absolute, it is unshakable, down to the detail. And very infectious.