Christians believe the Bible to be the Word of God because the Lord Jesus Christ believed it to be so.
He constantly referred to the Old Testament in His teachings. In every case His words show that He believed in its historic accuracy and Divine Authority. Here are three (of many) passage sources which show His attitude to the Old Testament, called by the Jews "The Law arid The Prophets".
- Matthew 5:17-19. Here Jesus underlines the Authority of The Law.
- Luke 24:27. Here He underlines the Message of The Prophets.
- John 5:39-40. Here He speaks of them as pointing to Himself as the source of eternal life.
He also gave the seal of His Authority to the New Testament in advance of it being written:
- Matthew 28:19-20. Here He commissioned His disciples to teach all nations
"Everything I have commanded you." This would have been impossible without
a written record.
- John 14:26. Here He promised that the Holy Spirit would bring back to their memories "Everything I have said to you."
- John 16:12-14. Here He promised that the Holy Spirit would teach them things they were not ready to understand at that time, but which were a vital part of His message
Therefore to believe that Jesus is the Son of God is to believe in the Divine Authority of the Bible.
Further, St. Paul wrote, "All Scripture is God-breathed." (2 Timothy 3:16), and it is clear from 2 Peter 3:16 that St. Peter regarded St. Paul’s writings as part of Holy Scripture.