From “Siyyag LeChokhmah,” an anthology on silence as a religious practice published by Mesilos HaTorah, Jerusalem (2000), p. 127. The “immersion in thought” mentioned below does not seem to be of an intellectual nature, but a meditative one.
The Meaning of "Echad (One)."
Translation by Dovid Sears
Sometimes Reb Menachem Mendel Kalish, Chassidic Rebbe of Vorki (d. 1868), would reach the level of hishpashtus ha-gashmiyus, severing his ties to the physical world, due to his practice of silence and deep meditation. Then his followers, among them Rabbi Moshe Kohen, would carry him to his private chamber and rouse him. Once it was hard to awaken him, and the Chassidim became extremely distressed.
Rabbi Moshe Kohen cried out, “Why is the Rebbe so fahrtracht (deeply immersed in thought)?”
Conscious of his surroundings again, the Rebbe replied, “If one knows the meaning of echad (One), it is impossible not to be immersed in thought.”
After Reb Menachem Mendel passed away, the saintly Rebbe of Biala, declared: “The Rebbe himself will lead us in the future, as well – for what did we hear from him? Words of Torah, he did not speak; rather, he illuminated us [in a way that transcended words]. And surely he will illuminate us in time to come!”