The way I approach questions like this is through the fact of God's trasncendent and personal nature. Some ask, "why can't I see God?" You can't see Him because His nature is beyond your own capacity and it is His choice to reveal Himself or not (since He is person). It's a fact, you can't deny it; it is simply the definition of trascendence, or else we are not truly talking about God, but a product of our imagination. So, "who made God?". Of course, He doesn't need to be made, He exists through Himself. Again, another fact, unless we want to talk about a God who by definition is not God. In a way, this is proof of God -- that He is the One who exists through Himself and is All-Powerful (He couldn't possibly not exist because His very name and definition attest Him). Ultimately, since God is unknowable through human means alone and by defintion exists through Himself, you are only left with denying Him, rejecting Him or accepting and loving Him. Honestly speaking, it's the only thing a human can actually do. And the Bible pretty much revolves around this fact taking God's existence and will as a given; actually God Himself reveals Himself as recorded in The Bible. In the Bible it is never presupposed that God exists or doesn't exist, but He simply reveals Himself and interracts with humanity. Arguments pro or against God's existence other than His trascendence are not really decisive, but they most definitely can act as supports, can help one know more about Him. Yet, ultimately you are left with a personal choice: either take the risk to reject or to accept Him.