I think it is very plausible to believe that some elements of the Bible might be true, others might be parable, and still others might have been made up by any number of the men who wrote and re-wrote and re-wrote the Bible.
The "either it's all true or it's all a lie" approach you seem to be advocating is odd to me, considering that at least some of it is acknowledged to be a parable.
Did not God himself write the words on the tablets of stone?