Ali ibn Muhammad ibn 'Abdallah has narrated from Ahmad ibn Muhammad from Muhammad ibn Khalid from Sulayman ibn Ja'far al-Ja'fari from the person who he mentioned from abu 'Abdallah (a.s.)
who has said the following.
"Imam Ali (a.s.) said, 'One of the rights of a scholar is that one must not ask him a great many questions and must not hold to his garment (excessive questioning).
When one would enter in his presence while other people are there one should offer salutation to all of them and special greetings to the scholar only. One must sit before him and not
behind him.
One must not blink his eyes before him or make hand gestures and must not speak much in his presence such as so and so said so and so opposite to what he says.
The length of his meeting must not disappoint one because the case of a scholar is like a fruit bearing tree in which case one needs to wait until three lets fruits to fall onto one. The
reward for a scholar is greater than that for one who fasts and prays very often and those who fight for the cause of Allah.'"