Lot of stuff on this subject. Again, I don't pretend to be an expert but let me offer this.
The beautiful thing about believing in God is that you dont have to have proof to know that he exists.
You are right, the Bible was written by men...yet it is the word of God. Men such as prophets and priests and saints are less men than channels that allow God to reach the rest of us. The dictionary is also just words, and yet it defines every word in the English language...
God makes his actions through people, and those people's actions are God. Moses did all of his work in Egypt for and by God. Without God, the chosen people would have remained slaves. Noah built the ark as a result of God's will. God did not want humans to go extinct, so he acted through Noah and his family.
People quote the Holy Bible because they respect its wisdom. Even if one does not believe in God, they cannot deny that the Bible lays down wonderful moral guidelines.
The proof of God is shown individually by God. Everyone has their own experiences that proves to them that God is watching over them. If you have not had your experience yet, do not despair. It will always come to those who are truely devoted to Him. And He is always ready toa ccept those who do not follow Him, whenever they decide to turn to Him for guidence.
What I have come to know from this is that God has a plan for each of our lives. We should seek him and ask for his wisdom and guidance.
It appears that we all choose/refuse to believe something.
English Standard Version (ESV)
8 For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, 9 not a result of works, so that no one may boast. 10 For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.