THE BIBLE WAS WRITTEN OVER CENTURIES AND IT WAS BROUGHT TO US BY FAITH. Faith Is Not A Belief In A Wish, But The Confidence of Reality. Therefore the historical witness of the Bible should stand the test of time--and it does!
As to when the Bible was written, we all have to rely upon what historians tell us. There is no actual date within the Bible that tells when each of the original authors composed their writings.
The Old Testament was obviously written before the New Testament. The New Testament has been criticized as having been written by people other than the authors to whom the books attribute authorship.
However, in the Gospel of Luke we learn that the reason the book was written was to provide an accurate record of the events that took place. This was also the case with the book of Acts, which was written by the author of the Gospel of Luke.
The one thing that is obvious in all the New Testament writings is there is no mention of the rebellion of the Jews in 66 AD or the fall of Jerusalem 70 AD. This suggests that the books of the New Testament were written before 70 AD or even 66 AD.
In the gospels, Jesus predicts a coming terror for the Jews. Had the writers known about the fall of Jerusalem, which they would have heard about as they were mostly Jews, they would have claimed that this was the fulfillment of the prophecy made by Jesus. Since there is none, it is natural and logical to assume that the New Testament was written before 70 AD.
In the case of the books of Luke and Acts, written by a Gentile who set out to provide a historically accurate record, had these been written after the 66 AD, then the events that occurred in Jerusalem that brought about the destruction of the city would have been mentioned.
The Old Testament book of Daniel predicts events that would occur in respect to Babylon, Medo-Persia, Macedonia, Seleucids, Ptolemies, and the Jews. The accuracy of these predictions have given cause for the likes of Porphyry of Tyre (234–305 AD) and others to claim they were written after the event, because people cannot predict the future.
The book of Exodus has been proven remarkably accurate in detail from the sites that have been discovered, which demonstrates that the writer would have had first hand experience of those events. This places the writing of Exodus around 1500 BC, when the Hebrews were led out of Egypt by Moses and crossed the Red Sea—the site of which has been discovered.