What is the ruling on the prayer of congregants behind an imam who, after the prayer, stated that he was not in a state of ritual purity (wudu)? And are they required to repeat the prayer? And what is the ruling on the prayer of congregants behind an imam who led them in prayer while intentionally in a state of ritual impurity (hadath), whether major or minor? And is the hadith of Umar, may Allah be pleased with him, that he led the people in the Fajr prayer then found wet dreams on his garment, so he repeated (the prayer) but they did not repeat, an authentic hadith that can be relied upon, or is it weak?

If the Imam leads the people in prayer while being in a state of ritual impurity (hadath) or having ritual impurity (najasa) on him, his situation is one of two:

1. If the Imam was unaware of his state of ritual impurity or the presence of ritual impurity until the end of the prayer: The Imam's prayer is invalid, and he must repeat it. However, the prayer of the congregants (ma'mumeen) is valid, and they are not required to repeat it. This is the view of the majority of scholars, supported by the hadith of Al-Bara' bin 'Azib and the narrations from 'Umar and 'Uthman, may Allah be pleased with them both. 2. If the Imam knew about his state of ritual impurity or the presence of ritual impurity before the prayer or during it: His prayer is invalid, and the prayer of the congregants is also invalid. All of them must repeat the prayer, because he violated a condition of prayer despite being able to fulfill it.