You are making the presumption that none of the Christian bible was divinely inspired, which is inevitable if you refuse to admit the existence of God. And there is far more evidence for the divine inspiration of the Christian bible than there is for the Qur'an
Don't think the Muslims will be agreeing with you there, Al, since everything you say about the Bible (spectacularly and pacifically its historically later and rather more slender component) is exactly what they say about their book.
See how this works? You have no more evidence for the credibility of your book than they do for theirs. And the same goes for their book as compared to yours similarly, likewise and contrariwise. Formally it's called the Argument from Inconsistent (sometimes: Competing) Revelations. In short, it's a great big theobabblilogical game of "He said, she said." (Without the 'she' component, obvs. Monotheism not really favouring the distaff side of humanity and all that. So it's more like 'He said ... no, he said ... no, he said ... no, he said ...' ... there's a fairly famous Monty Python sketch which - I assume unintentionally, notwithstanding the later films - encapsulates the entire history of theism within a few minutes. Highly recommended).
Good luck with that one.