The Old Testament of the Bible and much of the New Testament is focused on Israel. When we look at Jews today (who are their descendants), and the modern state of Israel, we observe the following:-
These observations show that the Bible is authentic.
The Bible mentions several places in Israel and elsewhere. These places exist today, and their geographical features that we see today are consistent with those given in the Biblical accounts. Some examples:-
Seas: The Bible mentions the Sea of Galilee as teeming with fish and the Dead Sea as "dead". Both these features are visible today.
Jerusalem-Jericho: The Bible mentions Jerusalem as a city at a high altitude, Jericho as a plain, and the road from Jerusalem to Jericho as being downward sloping and deserted (see Luke 10:30). I've gone that road by bus, and it is just like the Bible says it is. More details
Lushness: The Bible mentions the land as being arid when the Jews are scattered out of Israel, and blooming with life when they return. The last hundred years have illustrated this contrast very well.
City Names: Names of small towns and mountains mentioned in the Bible have persisted to this day: Carmel, Gilboa, Tabor, Nazareth, Bethshean, Bethlehem, Hebron, Shechem, Golan, Kidron Valley, the Garden of Gethsemane, the Mount of Olives, the valley of Hinnom, Caesarea, Engedi, Gaza, Ashdod, Jaffa (Joppa), Judea, Samaria, Tiberias, Nain, Bethsaida, Beersheba, Bethphage, Bethany, Eilat (Elath), etc.
Nazareth: The Bible says that when Jesus "told it like it is" at the Nazareth Synagogue (Luke 4:23-29), the citizens were so enraged with him that they tried to throw him off a precipice near their city. There is indeed a precipice just outside Nazareth. The image shows the panoramic view from the precipice, looking eastwards towards Mt Tabor.
"Luke is a historian of the first rank; not merely are his statements of fact trustworthy...this author should be placed along with the very greatest of historians" [Skeptic-turned-Christian Sir William Ramsay (1851-1939), archaeologist and professor from Oxford and Cambridge universities, Bearing of Recent Discoveries on the Trustworthiness of the New Testament, Baker, Michigan, USA, p.222, 1953]If you read the Gospel of Matthew, you can make out that he lays an emphasis on prophecy being fulfilled. In AD 32, Jesus predicted that the Jewish Temple in Jerusalem would be destroyed (see Matthew 24:1-2); this was fulfilled in AD 70. Thus, Matthew would have surely recorded the destruction of the temple if he was writing after AD 70. This event finds no record in Matthew's gospel, and hence we conclude that Matthew wrote before AD 70 - a few years after the events of Jesus' life took place. Note that Matthew was a disciple of the Lord Jesus who accompanied him wherever he went. Fragments of Mark's gospel have been found dating to 50 AD (Glendale News Press, Saturday, April 15, 1972, United Press International, Louis Cassels). This shows that if there was anything inaccurate in the gospel of Mark, it would have easily been discredited, since it was written when eye-witnesses were still alive. The same argument applies to Paul's lengthy description of the resurrection in 1 Corinthians 15:1-9, which he wrote in 54 AD. Luke stops the account of Paul's activity at his first imprisonment in Rome (60 AD) although Paul went on to do and travel much more. This suggests that Luke wrote shortly after 60 AD. Some more evidence to the eye-witness nature of Matthew, Mark, Luke, John and Acts is as follows:-
One test of authenticity is the acceptance of the book by the earliest audience. This is because, compared to us, the earliest audience was in a much better position to judge the historical and geographic accuracy of a book.
The Jews accepted the Old Testament of the Bible. Thus, given that the Jews who lived shortly after Daniel accepted the book of Daniel, the onus lies on the skeptic to prove why Daniel is false. What does he know about Daniel that the people of Daniel's day did not know?
The writers of the New Testament stated that they are not preaching "cunningly devised fables" (2 Peter 1:16). They also stated that the events that they write were witnessed by many people who were still alive then (1 Corinthians 15: 6, Luke 1:1-4). If the New Testament contained factual errors, its immediate audience would have discredited it and Christianity wouldn't have spread.
At this point it is worth noting that the Christians in the first century AD were mostly Jews, who, due to their heritage, were well read. Even the Greco-Roman culture was well read, and therefore, any book (especially one which claims to be authoritative) would be read and evaluated, at least by people who would consider joining the movement it represents.
Thus, the early spread of the New Testament and the faith it advocates proves that the central events of the New Testament, namely, the death and resurrection of Jesus Christ, and the characters and places involved, etc. were verified by those interested.
To summarize: early acceptance is evidence for the authenticity of both the testaments of the Bible.
If several people write about the same events honestly, they should agree with each other. This is indeed the case in the Bible. A few examples:
The four biographies of Jesus given in the Bible are consistent with each other.
The historical narratives of Kings and Chronicles agree with each other.
Without being in contact with Jesus during his earthly ministry or his disciples, Paul was able to describe his death, resurrection and the last supper. This proves that the apostles were being honest in their reporting (and that Paul was indeed being guided by the risen, ascended Christ).
Another example of consistency is found in Luke's reporting of the trial of Stephen (Acts 6:8 onwards, about AD 35). In his defense, Stephen quoted Moses (who lived in the 15th century BC and wrote the first five books of the Bible). So here we have three Bible characters:-
Here are various scenarios and the questions they raise:-
"In my college days, I foolishly listened to ungodly professors who sought to undermine my faith. They told me that the Bible was filled with contradictions…that educated people no longer believed the Bible, that only ignorant country preachers believed in it. My faith was badly shaken, but instead of taking the word of infidel professors on these matters, I began to study and investigate for myself, and the more I found out about the Bible, the stronger my faith became…Nearly forty years of Bible study have given me a faith that cannot be shaken…I plead with you not to discard the Bible as being unworthy of your faith until you make an honest investigation of it." – Homer Duncan, Doors of Hope, p20
Various internal and external evidence establishes the authenticity of the Bible beyond all reasonable doubt. If you cannot trust the Bible because you find the evidence insufficient, you should also reject everything you've been taught about Alexander the Great, Nebuchadnezzar, Emperor Ashoka, Julius Caesar, etc. Also see:-