What is the ruling on praying the Friday or Eid prayer behind an immoral or innovative Imam?
Chapter on Imamate and Congregational Prayer
Al-Mughni
Book of Prayer
Primary text
The Friday and Eid prayers must be attended behind every righteous or wicked person. Ahmad himself used to attend them with the Mu'tazilites. This is because these prayers are manifest symbols of Islam led by established authorities, and abandoning them leads to abandoning them entirely. If the prayer is performed behind one whose leadership is normally subject to repetition, repetition for Friday prayer is generally not required according to one narration from Ahmad, who stated that whoever repeats it is an innovator, implying that the prayer suffices as mandated by the command to attend.
Supporting text
Ahmad indicated that if the designated leader is righteous but the authority appointing him is immoral or innovative, repetition is not necessary. There is another view that repetition is required. The correct view is that the Imam's personal conduct does not invalidate the prayer which is linked to the appointing authority, similar to unforeseen impurity or illiteracy of the Imam.