The Kabbalah's attempt at bringing the mysteries of Creation into closer proximity of man's own experience has expressed itself perhaps most radically through the vehicle of Chassidic thought and tradition. This revolutionary approach to Jewish spirituality was revealed through the 18th century saint and healer, Rabbi Israel Ba'al Shem Tov. Initially a wonder worker, remedying human ills through both natural and supernatural means, the Ba'al Shem Tov slowly evolved into a facilitator and teacher who succeeded in revealing the unique capacity within every human being to directly elicit Divine grace and blessing.
His teachings emphasize those components of man's inner experience which correlate with the supernal forces discussed in classical Kabbalah. Hence, he advanced Kabbalistic contemplation beyond the realm of philosophical abstraction and into the sphere of immediate psychological insight. It was by delineating the interface between the sefirot and the human psyche that Chassidut hoped to bring Kabbalistic thought and practice to its final frontier.
The Ba'al Shem Tov's desire to proceed beyond Kabbalistic convention and forge a new path of service finds expression in the following story: It is told that the Ba'al Shem Tov once resorted to the use of a Divine Name in order to cross an impassable river, only to regret what he considered to be the unnecessary employment of a supernatural Divine power. After spending many years doing atonement for that one act, he once again found himself at the edge of a raging stream and crossed it by resorting to no more than simple faith.
It was this resource of faith, accessible to every Jew, and not the elusive powers of practical Kabbalah, which the Ba'al Shem Tov sought to tap in daily life. In the process, he distilled the essential spirit of Kabbalah, enhancing both its relevance and impact. Hence, while Kabbalah is referred to in the Zohar as the "soul of the Torah," Chassidut has been coined the "soul of the soul of the Torah."
Indeed, the classical tradition of Kabbalah can be considered chitzoni ("superficial") relative to that of Chassidut which, by focusing upon immediate experience, identifies aspects of Divinity which the highly formal and abstract system of Kabbalistic induction leaves unexplored.
The determinant of how deeply a particular tradition penetrates the mysteries of Divine being is the degree of bitul, or "selflessness," implicit in that tradition's approach. Chassidut, by emphasizing the innate Divinity of the Jewish soul, inspires a greater degree of bitul than classical Kabbalah with its focus upon the "evolution" of created being. Another way of saying this, consonant with the Ba'al Shem Tov's own terminology, is that Chassidut advanced the focus of the mystical tradition beyond the realm of olamot ("worlds," the reality of space and time) into the sublimer realm of neshamot ("souls").