It is narrated by Al­Daraqutni through ways of narration that he deemed to be weak. Know ­ may Allah have mercy on you and us ­ that the scholars unanimously agreed that it is permissible for one to offer Salah led by another who is not known to have committed any Bid`ah or any act of disobedience. It is not a condition for the Ma'mum (a person being led by an Imam in Prayer) to know the beliefs of his Imam or to test him in order to know his `Aqidah (creed). Rather, the Ma'mum is to pray behind the Imam without knowing the particulars of his beliefs. If the regular Imam, such as the Imam leading Jumu`ah prayer, the prayers of the two `Eids, or the Imam leading prayer in Hajj on the Day of `Arafah, happens to be Mubtadi` (one who introduces innovations in religion) who calls people to adhere to his Bid`ah (innovation in Islam) or a manifest Fasiq (someone flagrantly violating Islamic law) and the Ma'mum cannot find another Imam to offer congregational Salah behind him; in such cases the Ma'mum is required to offer prayer behind these Imams according to the opinion of the majority of the Salaf (righteous predecessors) and other Muslim generations of scholars who came after them. Accordingly, the one who neglects offering Jumu`ah and congregational Salah behind a corrupt Imam is a Mubtadi` (one who introduces innovations in Islam) according to the opinion of the majority of Muslim scholars. The sound opinion is that one is to offer Salah behind such Imam and not to repeat offering the same Salah afterwards. The Companions (may Allah be pleased with them) used to offer Jumu`ah and congregational Salah behind wicked Imams without repeating them. Also, `Abdullah ibn `Umar (may Allah be pleased with him) used to pray behind Al­Hajjaj ibn Yusuf as well as Anas ibn Malik (may Allah be pleased with him) as mentioned before. `Abdullah ibn Mas`ud (may Allah be pleased with him) and other Companions used to pray behind Al­Walid ibn `Uqbah ibn Abu Mu`ayt who used to drink alcohol and as a result offered four Rak`ahs of Fajr prayer instead of two. He then suggested to offer more Rak`ahs. It was said to him by Ibn Mas`ud, "You have already prayed more than is due." In Sahih Al­Bukhari, it is narrated that when `Uthman (may Allah be pleased with him) was placed under in house arrest, a person led people in Salah. Someone said to `Uthman, "You are the Imam of all the Muslims but the person who led people in Salah is an Imam that will cause affliction." He replied, "O nephew, verily, Salah is the best thing that people can do. Thus if they do it properly, then do it along with them. But if they do it improperly, then avoid their wrong."