The Salah of both the Fasiq (someone flagrantly violating Islamic law) and the Mubtadi` (one who introduces innovations in Islam) is in itself valid. If the Ma'mum offers Salah behind such Imams, his Salah will be valid. The scholars who disapproved of performing Salah behind such Imams based their disapproval on the obligation of enjoining what is good and forbidding what is evil. In addition, the one who publicly practices Bid`ah (innovation in Islam) and corruption is not to be appointed as a leader of Muslims because he deserves blame so that he may repent. If we can abandon him until he repents, this will be good. Some people may avoid being led by such Imam in Salah and offer it behind another Imam in hope that this will lead to resisting evil and will prompt him to repent or else be replaced, or so people may cease to imitate his evil practices. If this is the case, abandoning him will lead to a Shar`i benefit, especially that the Ma'mum will miss neither the Jumu`ah nor the congregational Salah, as they will offer them in some other Masjid (mosque) behind another Imam. However, if the Ma'mum, by doing so, will miss the Jumu`ah and the congregational Salah, his act will be that of a Mubtadi` and thus contradicting the conduct of the Companions (may Allah be pleased with them). Also if the Imam is appointed by those in authority and there is no Shar`i benefit in not performing Salah behind him, it will not be permissible to leave Salah behind him. Rather, offering Salah behind him will even be preferable. Thus, if one can remove an aspect of evil concerning leading Salah, it is incumbent to do so. Yet, if such Imam is appointed by those in authority and one cannot stop him from leading people in Salah, or that one can stop him doing so but with greater harm, it will not be permissible to get rid of little harm by incurring a greater degree of it. Also, it is not permissible to get rid of the lesser of two evils by doing the greater of the two. The divine laws are meant to achieve and protect interests, and to eliminate evils or reduce them as much as possible. Not performing Jumu`ah and congregational Salah has greater harm than offering Salah behind a corrupt Imam, especially when missing them does not lead to the removal of corruption. In such case, the Shar`i benefit will be thwarted without removing the evil. If one can perform Jumu`ah Prayer and the congregational prayers behind a pious Imam, then this is better than offering them behind a corrupt one. As for one who prays behind a corrupt Imam without an excuse, his case is disputed by scholars; some said he has to repeat his Salah while others said he does not have to. This issue is explained in the books of Fiqh that deal with secondary questions. [Here ends the words of the commentators]. What is most accurate regarding the question mentioned above is not to repeat the Salah, due to the evidence mentioned above. In origin, repeating Salah is not required. They need not be repeated except with a special proof requiring that and we know not for sure that such proof exists. Success is only from Allah.