And from him, from Sheikh Abu Sa'id Maymun ibn al-Qasim al-Tabarani—may Allah brighten his face—who said: I asked my master al-Jali—may Allah sanctify him and raise his rank—regarding the word of Allah, Mighty and Majestic: {Call them by [the names of] their fathers; it is more just in the sight of Allah. But if you do not know their fathers—then they are [still] your brothers in religion and those entrusted to you (mawalikum). And there is no blame upon you for that in which you have erred but [only for] what your hearts intended. And ever is Allah Forgiving and Merciful} (Al-Ahzab: 5).
(71) And among what has been related in the reports: "He whose spiritual fatherhood is not established, his brotherhood is not valid."
He said: My hearing of this is from my sheikh Abu Abd Allah al-Khasibi, may Allah ennoble his station, that its meaning is: if a believer meets a man and is told that he is a believer, he should investigate him and ask him about his spiritual fatherhood. If it is found to be sound, then he is his brother in religion, according to the saying of the Mighty and Majestic: {Call them by [the names of] their fathers} (Al-Ahzab: 5). If he has no father, then he is your brother in religion without fatherhood. If he calls you "father" and asks that of you, and you perceive maturity in him, then impart to him the knowledge of Allah the Exalted, and you shall be his master (mawla).
By the chain of transmission from Abu Sa'id Maymun, who said: I asked Abu al-Husayn al-Jali—may Allah brighten both their faces—regarding a believer hearing [knowledge] from his worldly father in the human realm? He replied: "This is void and impossible. I asked our master and sheikh al-Khasibi regarding this, and he said: 'It is not permissible for a man to impart the knowledge of Allah to his worldly child,' based on the word of the Mighty and Majestic, censuring the disbelievers: {And similarly, We did not send before you any warner into a city except that its affluent ones said, "Indeed, we found our fathers upon a religion, and we are following in their footsteps"} (Al-Zukhruf: 23).