God provides us great mountains of evidence for his existence, and also that the Bible is inspired by God. In Romans 1:20 we are told (and I completely agree as a scientist) that the existence of God is obvious from what was created. The evidence for design in nature is absolutely overwhelming. The evidence for the resurrection of Jesus is very strong. But, God gives us free will and he does not force us to believe. He does not speak to us from air or drop notes to us from the sky because he leaves room for doubt. Belief is a choice, based on evidence beyond a reasonable doubt, but not beyond all doubt. Like I said, because God loves us, he does not give us in-your-face evidence of his existence.