Good point. So, the Bible has no credibility and use as a major part of Christianity?
Well it is a major part of Christianity because the teachings and beliefs
are derived from what is written in the Bible. The Old Testament is basically the same in Islam, Judaism and Christianity with all the familiar names such as Moses and Abraham, and the New Testament is basically what Christianity is about and how it originated. It's just, in my point of view, I don't think it is a very credible source historically and factually. When they were writing, their purpose would have been to spread the Good News, hence, giving way to bias and maybe tendencies of exaggeration (after all...they are humans) and what better way of making people understand than to apply it to the social norm of the time? Of course, that is my interpretation so there are those who literally believe what is written.