Many muslims falsely believe things about Jesus that have been passed down from many generations, such as that the christian bible is corrupt. Many of them also believe things of their own religion that doesn't make sense. For example, tell them that it is absolutely impossible that one can keep track of all their wrong doings, and try and balance them out by doing good. Also, God doesn't need us, he wants us to be forgiven because he loves us, he doesn't need us nor does he require our works because the bible says "for by grace are ye saved through faith and that not of yourselves it is a gift of God not of works lest any man should boast." The bible also says "no flesh shall glory in his presence". So when a muslim tries to balance his bad deeds out with good deeds it is futile. Also, the bible says that we are born sinners, so we do bad deeds because we are bad. We don't do good deeds because we are good, but we try to do these to try and be good. So by doing good deeds doesnt change the fact that man has a sin nature.