The winter of 5642 (1882) was a period of unrest and trouble for Russian Jewry. My grandfather, the Rebbe, Rabbi Shmuel, spent an extended time in St. Petersburg on communal affairs, and called a number of meetings of leading Jewish figures. At one of these gatherings someone asked him what the first Chabad Rabbi, Rabbi Shneur Zalman of liadi, had contributed with the founding of the Chasidic movement.
Rabbi Shmuel answered, with the founding of the Chasidic movement Rabbi Shneur Zalman contributed the principle that man know his shortcomings, and that deficiency is a disease.
The man who realizes that he is ill will seek a remedy, and the Healer of the sick will send him his cure. Not so in the case of an individual who supposes himself healthy. It is said that Mashiach will heal all the afflicted, except the fool, because the fool doesn't even know he is sick. A fool is not merely unaware of his foolishness; he considers himself wise. He fails to perceive any light that is good. 1 He considers darkness to be light.
