Why the bible?
A basic reason to consider the bible as a basis for believing in God is because of what it says about itself:
Example: 1 Thessalonians 2:13 ESV
And we also thank God constantly . . . that when you received the word of God, which you heard from us, you accepted it not as the word of men but as what it really is, the word of God, which is at work in you believers.
Example: 2 Timothy 3:16-17 NIV
All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, so that the servant of God may be thoroughly equipped for every good work.
Example: 2 Peter 1: 20-21 ESV
Knowing this first of all, that no prophecy of Scripture comes from someone’s own interpretation. For no prophecy was ever produced by the will of man, but men spoke from God as they were carried along by the Holy Spirit.
Example: Romans 15:4 ESV
For whatever was written in former days was written for our instruction, that through endurance and through the encouragement of the Scriptures we might have hope.
Jesus also relied upon the scriptures as a basis for his knowledge of God, the Father.
Example: Matthew 4:4 NIV
Jesus answered, “It is written [in the scriptures]: ‘[Humankind] shall not live on bread alone, but on every word that comes from the mouth of God.’”