I appeal to you therefore, brothers, by the mercies of God, to present your bodies as a living sacrifice, holy and acceptable to God, which is your spiritual worship.  Romans 12:1

That is a fair question.  The fundamental answer to that question is that we should believe the Bible because it is the word of God (2 Tim. 3:16).  The Holy Spirit Himself must transform our hearts, removing our spiritual blindness and humbling our natural rebellion against God, in order for us to receive His word (1 Cor. 2:14).  No mountain of evidence will ever be able to overcome our innate opposition to the things of God without this supernatural work of the Holy Spirit (Luke 16:31).  But that is not to say that there is no evidence attesting to the fact that the Bible is what it says it is: the inspired, inerrant, infallible, trustworthy word of the Living God.  Here are some evidences of the Bible's divine origin:

  • The Bible claims to be the Word of God: Psalm 19:7-11; Psalm 119:97-104, 130; Matt. 21:42; Matt. 22:31-32, 43; Matt. 26:54, 56; 2 Tim. 3:16-17; Heb. 4:12; 2 Pet. 1:19-21
  • The Bible contains fulfilled prophecy, especially about the birth, life, death, and resurrection of Jesus: Gen. 3:15; Psalm 2:1-12; Psalm 16:10; Psalm 22:1, 7-8, 14-18; Psalm 110:1-7; Micah 5:2; Isaiah 7:14; Isaiah 9:6-7; Isaiah 53:1-12
  • The Bible's revelation of God is beyond human imagination: Ex. 15:11; Psalm 89:6-8; Psalm 97:9; Psalm 113:5; Psalm 115:1-18; Isaiah 55:8-9; Rom. 11:33-36
  • The Bible's doctrine of human depravity is not what men typically say about themselves: Gen. 6:5; Gen. 9:20-21; Num. 20:12; 2 Sam. 11:27; Isaiah 53:6; Mark 14:72; Rom. 3:10-18; Gal. 1:13; Eph. 2:1-3; 1 Tim. 1:15
  • The Bible's doctrine of salvation uniquely debases the pride of man and exalts the grace and glory of God: Rom. 3:20-28; 1 Cor. 1:18-29; 2Cor. 5:21; Gal. 3:13; Eph. 1:3-6; Eph. 2:8-9; Phil. 3:8-9
  • The Bible has been extraordinarily preserved and accurately transmitted to us down through the ages: Isaiah 40:8; Matt. 5:18; 24:35; John 10:35; Rev. 1:3; 22:7, 18-19; http://www.icr.org/bible-manuscripts/; http://carm.org/manuscript-evidence; http://www.provethebible.net/T2-Integ/B-0801.htm

Here are some resources to reinforce your faith in the Bible: