by their statements, 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 factor 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.

Section: If he does not know of his Imam's wickedness or his innovation until he has prayed with him, then he must repeat it. This is explicitly stated. Ibn 'Aqil said: 'He is not obliged to repeat it,' because this is something hidden, so it is similar to [praying behind] one who is in a state of ritual impurity or is impure. The correct view is that this must be examined; if he is someone who hides his innovation and wickedness, the prayer behind him is valid, based on what we mentioned at the beginning of the issue. But if he is someone who displays this, it is obligatory to repeat the prayer behind him, according to the report which states that it is obligatory to repeat it behind an innovator. This is because it is a factor that prevents one from following him, so knowledge and lack of knowledge of it are equal, just as if he were illiterate. Ritual impurity and impurity are conditional upon being hidden from both the Imam and the follower, and a sinner cannot hide his sin from himself. Furthermore, repetition is only obligatory behind one who openly declares his innovation, and this is not a matter that is likely to be hidden, unlike ritual impurity and impurity.

Section: If he does not know his state and nothing that would prevent following him has appeared from him, then the follower's prayer is valid. Ahmad explicitly stated this, because the basic principle regarding Muslims is their integrity. If one prays behind a person whose Islam he doubts, his prayer is valid, because the outward appearance is that no one would step forward to lead the prayer except a Muslim.

Section: As for those who differ in secondary matters (furu'), such as the followers of Abu Hanifah, Malik, and al-Shafi'i, the prayer behind them is valid and not disliked. Ahmad explicitly stated this, because the Companions, the Successors, and those who came after them never ceased to follow one another despite their differences in secondary matters; thus, this constitutes consensus. Also, the dissenter is either correct in his Ijtihad,