This is another article in the chapter Sufism from the classical manual on Sharia called Reliance of the Traveller. The articles are posted one by one in the order they are given in the book.
w9.6 (Ahmad Zarruq:) The conditions of a sheikh to whom a disciple may entrust himself are five:
(a) sound religious knowledge;
(b) true experience of the Divine;
(c) exalted purpose and will;
(d) a praiseworthy nature;
(e) and penetrating insight.
Someone with all five of the following is not fit to be a sheikh:
(1) ignorance of the religion;
(2) disparaging the honor of the Muslims;
(3) involvement in what does not concern him;
(4) following caprice in everything;
(5) and showing bad character without a second thought.
If there is no sheikh who is a true guide (murshid, def: w9.7), or there is one, but he lacks one of the five conditions, then the disciple should rely on those of his qualities that are perfected in him, and deal with him as a brother (A: meaning the sheikh and disciple advise one another) regarding the rest (Kitab qawanin hukm al-ishraq ita kaffa al-Sufiyya fi jami’ al-afaq (y121), 119).