Once, a group of Hasidim approached the Maggid of Mezeritch and told him that they lived far away and needed someone to be their guide and teacher.
They suggested Rabbi Menahem Mendel of Vitebsk (who in fact became a kind of successor to the Maggid after his death) and asked how they could determine whether he was the right man.
What are the criteria by which to measure whether he is truly a great man?
The Maggid responded, “Ask him whether there exists any method of avoiding pride.
If he gives you such a method, you will know that there is no substance to him.”
When they posed the Maggid’s question to Rabbi Menahem Mendel, he answered, “What can I tell you? One person might wear sackcloth and filthy clothing, and his heart might still be full of pride, whereas someone else may walk erect and dress elegantly, yet his heart may be broken inside him. There is no method for this.”
Rabbi Adin Steinsaltz