Some medieval Christian polemicists acknowledged Muslim salvation required good works beyond mere confession

Evidence

In spite of this criticism, there was some recognition that good works at least bore upon salvation in Muslim belief; thus, in a summary of Islam, Mark said that there is resurrection and eternal life for those who believe and do good (bona faciunt); and Tripoli spoke of Paradise as reward for serving Muhammad’s religion well, not just for serving it. Mandeville asserted that the good were to go to Paradise and the evil to Hell, and Acqui spoke of the pains of Hell, not only for those who do not believe in Muhammad, but also for those who do not ‘serve his perfect law’. — Norman Daniel, Islam and the West, 888