When introducing the initiative for appointing personal mashpi'im, in addition to the already-appointed community mashpi'im, the Rebbe set criteria regarding whom one should choose as a mentor.
Firstly, said the Rebbe, a mashpia must have the three qualities that characterize Yidden in general: he must be compassionate, bashful and kind – visibly so, and to a degree appropriate to his position.
Secondly, Chazal teach that one should learn Torah from a rav who resembles a malach. This means that the rav should be far removed from personal bias and envy, so that he can advise a fellow Yid without any personal interests involved.
(תו"מ תשמ"ז ח"ב ע' 632, 691)
CONSIDER
Why does the personal lifestyle of the teacher matter, if what he is teaching is true? How does one know who is worthy of serving as an example for chassidim?
