The Alter Rebbe once told his brother, Rabbi Yehuda Leib (author of She'erit Yehuda), about his first visit to his teacher, Rabbi DovBer, the Maggid of Mezritch. Rabbi Yehuda Leib later related the account to Rabbi Menachem Mendel, third Rebbe of Lubavitch.

Once the members of the chasidic fraternity1 were discussing the various levels of angels associated with the Divine Chariot and the counterparts of these angels in every world. 2 One of the disciples spoke of the angels as Abstract Intellects whose very life is the Word of G‑d.3 Another spoke of those celestial beings as continually in alternating states of Love and Fear, of advance and retreat; 4 another, of still loftier beings. Several of the disciples discussed the sefirot5 of Atzilut, elaborating on the superiority of tiferet over the other attributes, the superiority of bina over the emotive-attributes, and the superiority of chochma over bina, etc. All these have this in common: they are intellectual emanations possessing knowledge and understanding, each praising and glorifying its Creator in its own way.

The impassioned discussion of the wondrously sweet service of the heavenly beings, and envious of that exalted level, kindled a fire of longing for G‑d in the hearts of all the disciples. They were overwhelmed by a state of ecstasy. Moving their lips silently, they trembled and wept. Some stood with faces flushed, eyes shining, and hands outstretched, as though thunder-struck. Others among them sang quietly, their hearts bursting, and their souls on the verge of expiration in intense yearning to cleave to their Maker.

My brother told me, related Rabbi Yehuda Leib, that this scene clarified for him the words of Rabbi Shimon bar Yochai, 'I bound myself with a single bond, I became one with Him; I was aflame with Him.'

No doubt, continued my brother,had the Maggid not entered the hall at that moment, some of the men would have simply expired as a result of their tremendous yearning and desire to unite with the Almighty. But as soon as the Maggid's footsteps were heard, the entire group instantly came out of their reverie and prepared themselves to receive their mentor.