where did god come from?
Why is there anything, instead of nothing? One of the philosophical reasons to believe in God is the Cosmological Argument, which explains that everything must have a cause...and the initial cause for everything is a being which we call "God". Anything other than this explanation requires an infinite regress (essentially that everything has always existed) for which there is no evidence. Assuming one accepts the notion of a first cause, it begs the question, "what caused God?"
But the answer within the Cosmological Argument gives us the answer to this question also! By definition, God is the first event, sometimes known as the 'Prime Mover'. Therefore by this definition, God is uncaused. So the question 'Where did God come from?' is improper. It is like asking for a square circle, or a flat ball. Is it hard to accept? Yes. But does it make sense to us? Yes, in the sense that we intuitively know that there cannot be an infinite regress of events. SOMETHING had to be the first. There is nothing in nature that we see coming from nothing (despite the fifty dollar words some Naturalists throw around, like quantum fluctuations, etc.) It is just not practical. So what started it all off? Something outside of nature - something supernatural.
What's the alternative? If you don't want to believe in a Creator, you must either believe that something (indeed, everything!) came from nothing, OR you must believe that everything has always existed. NEITHER are reasonable, since they contradict everything observed. There is no evidence for it, in fact the evidence points toward a beginning (second law of thermodynamics), and evidence points to nothing coming from nothing (if someone has seen something come from nothing, I'd love to see it!) Therefore, it is REASONABLE to believe that there is a Creator!
While this philosophizing does not prove the God of Christianity, it does establish that the belief in a 'Prime Mover' is reasonable, based upon sound thinking formed from sound experience (the observations of cause and effect and the unreasonableness of infinite regress). Understanding this, the question now becomes: "What is the nature of this Prime Mover?"