New Testament scholar, Bart Ehrman, on his blog:
[O]ne question that I get frequently, especially from Muslim readers, is about the manuscript tradition of the Qur’an in relation to the New Testament. Even though I’m not an expert on the manuscript tradition of the Qur’an (oh boy am I not an expert), I know enough to answer with some authority this particular question. The question is whether…the Qur’an is more reliable than the New Testament. What the questioner almost always means by that is that the ancient manuscripts of the Qur’an tend to be amazingly similar to one another. Virtually identical up and down the line. Scribes kept it the way it was, without changing it. That’s in contrast to the New Testament, where scribes changed it all the time, often in insignificant ways and sometimes in rather startling large ways, either by accident or on purpose. Can we be far more certain that we know from early times exactly what form of the Qur’an was in circulation, based on current manuscripts, as opposed to the New Testament. Yes. Does that make it more reliable – i.e. that what it says is *true*? Of course not. It just means you have a better idea of what it originally said.
Sometimes an analogy helps. With the invention of printing we have far, far, far better accuracy in determining what an author wrote. There are still problems. But they are minor by comparison with manuscript traditions. When I publish a book, you know almost exactly what it was I wanted it to say, word for word. Almost exactly (unless, e.g., the press published a misprint). Does that mean what I wrote is true?
Put it in crass terms. If you have five million copies of Adolf Hitler’s Mein Kampf, and there are no differences among the wording of all five million copies, would you want to conclude therefore that [Mein Kampf] is more reliable, more “true,” than, say, the Qur’an or the New Testament? Of course not, the fact that you may know what a person actually said doesn’t make it true. You might think it was more true, but the fact that all the copies are the same has nothing to do with it.
I should point out that some [of] our Christian friends are guilty of this same untenable leap of logic as our Muslim friends. I frequently hear Christian apologists argue that since we have so many more manuscripts of the New Testament than for any other book in antiquity, we can therefore trust it. No, not true at all. We may choose to trust it, just as we may choose to trust the Qur’an. Or Cicero, or Homer, or Plato, or Aeschylus. But choosing to trust what an author says is not related to the question of how many manuscripts we have of the book, or of how accurate those manuscripts are.
End of post.