|The Great Isaiah Scroll, 1QIsa|
The Bible was written by about forty people over the course of fifteen hundred years who were inspired by God. It begins with books written by Moses fourteen hundred years before Christ. The New Testament Gospels were written by people who personally knew Jesus and were witnesses to His ministry. All the books collected together are a history of God's revelation to His people. They all form a cohesive story.
The Bible is most reliable document in all of antiquity. We have much greater evidence of its reliability than any of the ancient Greek documents. Take Aristotle. He was writing in the 4th century BC. The earliest copies we have of his work are from 1000 years later. The New Testament scriptures were written in the first century AD, while there were living eye witnesses, and there exist manuscripts from one to two hundred years after they were written. Most other ancient documents that we assume valid, the copies we have were not only dated many more years after they were written, but there are only a few copies. The New Testament we have thousands of manuscripts. As for the Old Testament there was a discovery in 1948 of ancient documents called the Dead Sea Scrolls. They are over 2000 years old and were untouched from that time being buried in a cave. Among them is a scroll of the book of Isaiah that was found to be exactly the same as the one we have today. The historical evidence is overwhelming in favor of the reliability of these documents.
In addition, Archeologist have been hard at work in the last two hundred years and they are continually discovering new archeological confirmation of the history documented in the Bible. Some historians thought the kingdom of David was a legend. But recently they have discovered a reference to the house of David engraved on a 3000 year old stone column in the Middle East. Another example is the people called Hittites who are mentioned in the Bible more than fifty times. Until the 19th century there was no historical or archeological evidence that these people existed. In 1876 in Turkey archeologist discovered a number of artifacts that included a storeroom with ten thousand clay tablets. It turns out this site must have been the capital of the Hittite Empire. Today there is no longer any question about the reality of their existence by Biblical scholars.
The idea that the Bible has been changed over time or has recorded only mythical stories is totally false. Even though there are some things that we still do not have historical evidence, we can see from the progressive unveiling of archeological evidence that this does not mean they did not take place historically. Of all ancient documents, the Bible is the most reliable we know. It has been carefully reproduced in a way to avoid any significant change.
We cannot let doubters discourage us. What is central to our Christian faith is our belief in Jesus who was sent to renew mankind, to free us from our sinful condition separated from God. He came not as a super human being, but as person both God and fully human. He took on flesh from a virgin. He showed us the way by His teaching, His miracles, and finally His voluntary death by Crucifixion at the hand of the Romans followed three days latter by his Resurrection. Then forty days after this He ascended in to heaven after instructing His disciples and within ten days sent to them the Holy Spirit which transformed them allowing them, against constant threat of death, to teach the good news about His Resurrection, His victory over death, and establish churches where the sacramental life could be practiced by all peoples for their salvation. We may not want to believe in the story of Noah and the great flood, although there is historical evidence of a world wide flood eight or ten thousand years ago, We should not let this distract us from the central truth of our faith, which is Jesus Christ. Our faith is not dependent to Noah building an ark but it does depend on the divinity of Jesus and His Crucifixion, Resurrection, Ascension to heaven and sending the Holy Spirit establishing His Church. For this the record of how it happened is well documented.
Reference: The New Testament Documents: Are they Reliable? by F. F. Bruce