Allah Most High, in the story of Moses (a.s.) and Khidr (a.s.), said, "Moses said to him [Khidr], Shall I follow you so that you will give me good guidance out of what you know?" (Kahf 66)
The Imam (al‑Qushayri) said: When Moses wanted the companionship of Khidr, he followed the prescribed behavior. First he asked permission to keep company with Khidr. Then Khidr specified that Moses should not oppose him in anything, or offer resistance to any decision. When Moses (a.s.) did object to Khidr’s actions, Khidr ignored this the first and second times. Then when the third time came ‑‑ and three is the end of "a little" and the beginning of "a lot" ‑‑ Khidr insisted that they part company. He said, "This is the parting between me and you."
I heard Abul-Husayn al‑Ahwazi say…from Anas ibn Malik, that the Messenger of Allah (s.a.w.s.) said:
No young man honors an old man [sheikh] in his old age without Allah Most High appointing someone to show him honor in his own old age.
I heard Master Abu ‘Ali al‑Daqqaq (r.a.) say:
The beginning of all separation is opposition.
By this he meant that whoever opposes his sheikh cannot continue in his path. The bond between them is severed even though they come together in the same place. Whoever keeps company with any sheikh and then resists him in his heart has wronged the vow of companionship. Such a person must repent, although the sheikhs have said, "There is no repentance for disobeying teachers."
I heard Shaykh Abu `Abdul‑Rahman al‑Sulami say:
During the lifetime of my sheikh, Master Abu Sahl al‑Su’luki, I traveled to the city of Merv. Before I left he was holding sessions for reading the Qur’an in the mornings between dawn and sunrise. When I came back I found that he had left that custom. Instead, at the same hour, he was meeting with Abul‑`Affani for singing sessions and audition. I wondered at this, and began saying to myself, "How could he want to substitute singing for reading the Qur’an?"
One day he said to me, "Tell me, Abu `Abdul‑Rahman‑ what are people saying about me?"
"They are saying, ‘He has given up Qur’an sessions for singing sessions!’” I replied.
"Whoever asks his teacher ‘Why?’ will never prosper!" said he.
It is well known that Junayd said, "One day I went to see Sari and he ordered me to do something. I immediately carried out the thing he needed. When I returned, he handed me a slip of paper and said, ‘This belongs to the place where you did what I needed so quickly!’ I read the paper.’ On it was written:
‘I heard a camel-driver urge on his camel in the desert, singing:
I wept—did you hear what made me weep?
I wept for fear that you would leave me.
Would cut my halter and not see me again!’”
It is told that Abul‑Hasan al‑Hamadani al‑`Alawi said, "One night I was with Ja’far al‑Khuldi. I had ordered a bird to be baked in the oven, and my heart was taken with that. Ja’far said to me, ‘Stay and pray with us tonight!’ but I made some excuse and went back to my house, took the bird out of the oven, and set it before me. Then a dog came in the door, and when no one was paying attention, he carried off the bird! So they brought the pastry that had been baked under the bird, but somehow the hem of the serving woman’s dress got stuck to it, and it fell on the floor.
"The next morning I went to see Ja’far. When his eyes fell upon me, he said, ‘Those who show no consideration for the hearts of sheikhs have dogs set over them to torment them!’"
I heard Sheikh Abu `Abdul-Rahman al-Sulami say ...Umm Bistami related from her father:
Shaqiq al‑Balkhi and Abu Turab al‑Nakhshabi went to visit Abu Yazid. A table was prepared. There was a youth waiting upon Abu Yazid. "Come, eat with us, young man!" the two of them urged.
"I am fasting," said he.
"Eat, and you will have the reward of a month’s fast!" said Abu Turab. The youth refused.
"Eat, and you will have the reward of a year’s fast!" said Shaqiq. Still he refused.
"Pray for someone who has fallen from Allah’s grace," Abu Yazid said to them.
In a year that young man had begun to steal, and his hand was cut off!
I heard Master Abu ‘Ali say:
Sahl ibn `Abdullah described a certain man as a saint. He was a baker in Basra. Another man heard this from the members of Sahl’s circle, and began to yearn after this saint.
So he went to Basra and came to the baker’s shop. There he saw the man baking bread. His face was wrapped to protect him from the fire of the oven, as is the custom of bakers. The traveler said to himself, "If this man were really a saint, his hair would not burn, even if he had no protection!"
He offered the baker greetings and asked him something. The baker said, "Since you think so little of me, why should I benefit you with my talk?" And he refused to speak to him.
I heard Sheikh Abu `Abdul‑Rahman al‑Sulami say:
`Abdul‑Rahman al‑Razi heard Abu `Uthman al‑Hiri describe Muhammad ibn al‑Fadl al‑Balkhi, praising him highly. So he conceived a desire to see him, and went to pay him a visit, but Muhammad ibn al‑Fadl did not make the impression on his heart that he had expected. He went back to Abu `Uthman and asked him about this.
"How did you find him?" asked Abu ‘Uthman.
"I did not find him to be what I thought he should be!" said `Abdul‑Rahman.
"You did not profit from him because you belittled him," said Abu `Uthman. "When a person thinks little of another person, that person’s special value and usefulness is denied him. Go back to Muhammad ibn al-Fadl with respect."
So `Abdul‑Rahman went back, and benefited from his visit.
There is a famous story that ‘Amr ibn `Uthman al‑Makki saw al-Husayn ibn Mansur [al‑Hallaj] writing something. "What is this?" he asked.
"Why, I am competing with the Qur’an!" said al-Husayn.
‘Amr cursed him and broke off relations with him.
The sheikhs say that what eventually befell al-Husayn was the result, after a long interval, of the curse of that sheikh.
I heard Master Abu `Ali al‑Daqqaq (r.a.) say:
When the people of Balkh threw Muhammad ibn al‑Fadl out of the city, he prayed against them. "My Allah," he prayed, "forbid them integrity!" And no man of real integrity has come out of Balkh since.
I heard Ahmad ibn Yahya al‑Abiwardi say:
If someone’s sheikh is pleased with him, he will not be rewarded for that during his lifetime, lest reverence for the sheikh should leave his heart. But when the sheikh dies, Allah Almighty and Glorious will manifest the reward for having pleased him.
If someone alienates the heart of his sheikh, that too will not be requited during the lifetime of that sheikh, lest the sheikh have sympathy for him, for sheikhs are prone to be generous. But when the sheikh dies then it will be paid for.
 Ahmed ibn ‘Ubayd al-Basri – Abu Salim al-Qazzaz – Yazid ibn Bayan – Abu Rijal.
 Abdullah ibn ‘Ali al-Tusi—’Abdullah al-Dinawari—al-Hasan al-Damghani—his uncle al-Bistami—the grand-uncle of al-Hasan al-Damghani