In short, Muhammad was an ignorant charlatan who succeeded by imposture in seducing the ignorant barbarian Arabs into accepting a gross, blaspheming, idolatrous, demoniac religion, which is full of futile errors, intellectual enormities, doctrinal errors and moral aberrations.
John of Damascus
From that time to the present a false prophet named Mohammed has appeared in their midst. This man, after having chanced upon the Old and New Testaments and likewise, it seems, having conversed with an Arian monk, devised his own heresy. Then, having insinuated himself into the good graces of the people by a show of seeming piety, he gave out that a certain book had been sent down to him from heaven. He had set down some ridiculous compositions in this book of his and he gave it to them as an object of veneration. … There are many other extraordinary and quite ridiculous things in this book which he boasts was sent down to him from God. But when we ask: ‘And who is there to testify that God gave him the book? And which of the prophets foretold that such a prophet would rise up?’—they are at a loss. And we remark that Moses received the Law on Mount Sinai, with God appearing in the sight of all the people in cloud, and fire, and darkness, and storm. And we say that all the Prophets from Moses on down foretold the coming of Christ and how Christ God (and incarnate Son of God) was to come and to be crucified and die and rise again, and how He was to be the judge of the living and dead. Then, when we say: ‘How is it that this prophet of yours did not come in the same way, with others bearing witness to him? And how is it that God did not in your presence present this man with the book to which you refer, even as He gave the Law to Moses, with the people looking on and the mountain smoking, so that you, too, might have certainty?’—they answer that God does as He pleases. ‘This,’ we say, ‘We know, but we are asking how the book came down to your prophet.’ Then they reply that the book came down to him while he was asleep.
Both Nicea and John of Damascus report of some errors in either the muslim belief or the Quran. Which are these errors? Which are those immoral acts and how do muslim apologetics respond to them?