The Rebbe instructed each chossid to fulfill the dictum of the Mishnah: “Asei lecha Rav”—“Appoint for yourself a teacher” (Avos 1:6), a personal guide and mentor.
Of course, one’s Asei lecha Rav needs to be intelligent, knowledgeable, sensitive, wise, insightful, refined, and so on. However, although these qualities are necessary, they are more external. The Rav’s ability to advise us depends upon his bittul to Hashem, and for chassidim, part of bittul to Hashem is bittul to the Rebbe, who is the “intermediary who joins” us with Hashem. So a chossid should seek an Asei lecha Ravwho possesses this quality. Then the Asei lecha Rav’s role is not to tell us ideas of his own, but to explain to us what the Rebbe wants of us.
Thus, when we go to an Asei lecha Ravfor counsel, we do not go to him as an individual (albeit one with wisdom and experience), but as an extension of the Rebbe, for “one’s agent is the legal equivalent of oneself” (Nedarim 35b).