There are 3 main tests to verify the accuracy and authenticity of Bible.
First is the Internal Test:
The Apostle Peter tells us:
2 Peter 1:16
16 For we have not followed cunningly devised fables, when we made known unto you the power and coming of our Lord Jesus Christ, but were eyewitnesses of his majesty.
Most of the Bible was written between 47 AD and 95 AD which means that there were people still alive at the time it was written who could have refuted what was written and could also verify what was written.
Also the writers do not show themselves in a great light, but show their weaknesses, doubts and fears. An example is when Jesus and His disciples were on a boat and a fierce storm came up and Jesus was asleep and the disciples panicked and awoke Jesus:
26 And he saith unto them, Why are ye fearful, O ye of little faith? Then he arose, and rebuked the winds and the sea; and there was a great calm.
27 But the men marvelled, saying, What manner of man is this, that even the winds and the sea obey him!
Second is the External Test:
What does History say? Let’s start the with writings themselves. There are over 5,000 copies of the original manuscripts of the New Testament alone written less than 100 years after the crucifixion and resurrection. These documents have been verified by many archeologists. The content has been verified the “Dead Sea Scroll” as well.
It may be stated categorically that no archeological discovery has ever controverted a biblical reference.
Flavius Josephus was a Jewish historian who was born in Jerusalem around A.D. 37. He died around the year 101. He is considered one of the best historians concerning the Jews and Christians at the time of Christ. In his writing Antiquities which is as a history of the Jews. he mentions Jesus.
“At this time there was a wise man called Jesus, and his conduct was good, and he was known to be virtuous. Many people among the Jews and the other nations became his disciples. Pilate condemned him to be crucified and to die. But those who had become his disciples did not abandon his discipleship. They reported that he had appeared to them three days after his crucifixion and that he was alive. Accordingly, he was perhaps the Messiah, concerning whom the prophets have reported wonders. And the tribe of the Christians, so named after him, has not disappeared to this day.”
Third is the bibliographic test:
When the Bible is translated into different languages it is usually translated from the original Hebrew and Greek by scribes. The scribe was considered a professional person in antiquity. No printing presses existed, so people were trained to copy documents. The task was usually undertaken by a devout Jew. The Scribes believed they were dealing with the very Word of God and were therefore extremely careful in copying. They did not just hastily write things down. The earliest complete copy of the Hebrew Old Testament dates from c. 900 A.D.
The Bible having met all 3 tests can be said to be the accurate and true representation of the Word of God.
2 Timothy 3:16-17
16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
17 That the man of God may be perfect, thoroughly furnished unto all good works.