Bakrah (21) said to him: 'Step away from our place of prayer, for we do not pray behind you.' The hadith of Abu Dharr indicates the validity of [praying behind them] as a supererogatory act, while the dispute concerns the obligatory prayer.

Section: As for the Friday and festival prayers, they are performed behind every righteous and wicked person. Ahmad used to attend them with the Mu'tazilah, as did the scholars who were in his era. We have narrated that a man came to Muhammad ibn al-Nadr (22) and said to him: 'I have neighbors among the people of innovation (Ahl al-Ahwa') who do not attend the Friday prayer.' He said: 'That is enough for you. What do you say about someone who refutes (23) Abu Bakr and 'Umar?' He replied: 'A wicked man.' He said: 'What if he refutes the Prophet (peace and blessings of Allah be upon him)?' He replied: 'He is a disbeliever.' He said: 'What if he refutes the Most High (al-'Ali al-A'la)?' Then he fainted, and when he regained consciousness, he said: 'Answer him: By the One besides whom there is no god, for indeed He said: "O you who have believed, when the adhan is called for the prayer on the day of Jumu'ah, then proceed to the remembrance of Allah" (24), and he knows that the Banu al-'Abbas will be in charge of it.' This is because this prayer is among the manifest symbols of Islam; the Imams perform it to the exclusion of others, so abandoning it behind them leads to abandoning it entirely. Once this is established, it is repeated behind those behind whom other prayers are repeated. Ahmad said: 'As for the Friday prayer, it is desirable to attend it, but if the one who leads the prayer among them [does so in a way that necessitates repetition], then he should repeat it.' It is also narrated from him that he said: 'Whoever repeats it is an innovator.' This indicates, by its generality, that it is not to be repeated behind a sinner (fasiq) or an innovator (mubtadi'), because it is a prayer that was commanded, so its repetition is not obligatory, like other prayers.

Section: If the person conducting it is just, but the one who appointed him is not considered acceptable due to his innovation or wickedness, he should not repeat it. This is explicitly stated. It was said to him: 'They say that if the person who appointed him says [according to their views, the prayer is void].' He said: 'I do not say this.' This is because his prayer (25) is only connected to the prayer of his Imam, so the presence of a defect in someone else does not cause harm, just like [the status of being] in a state of ritual impurity or being illiterate. There is another report from him that it is repeated. The correct view is the first one.