God created the universe? Please clarify what you mean by that, 'cause it makes no sense at all to me.
If anyone is tell us that God caused the universe to exist, they ought to be able to tell us the difference between an existing universe and a nonexisting one - and how we are to determine if we are in one or the other.
Snoopy flies around in the sky on his dog house, types funny letters, and talks to birds. Is Snoopy real? When Snoopy says he's real, how would Charlie Brown go about convincing Snoopy that he's wrong?
That may sound silly, but its not. It highlights a problem with the idea that, by whatever means, "the universe came to be." The problem with "the universe came to be" is that nobody knows what such a statement even means. It's just empty words.
God caused the universe? Can you clarify what you are claiming God did? Did it involve him considering a bunch of possible worlds and deciding to sprinkle magic pixie dust on the one he liked best? (If you say he used his magical God voice rather than pixie dust, that's fine - it doesn't affect the point I'm attempting to make - I am using pixie dust as a placeholder for whatever it is you want to say God did to make this universe exist.) Is it possible for God to have considered the inifinity of possibly worlds and then sprinkled magic pixie dust on just TWO of them? Or, in your view, are "real" universes limited to just one - even if God would have wanted more? If they are not limited to just one, would a god be malicious if she sprinkled magic pixie dust on ALL of them? I mean, some of those other possible universes are unimaginably horrible, and the inhabitants suffer without any hope of salvation. (For god to include salvation in the world would be a different possibilty, here we are looking at the possiblity of him not offering salvation.) Or was God like Santa Clause holding a naughty and nice list and sprinkling magic pixie dust only on the good possible worlds, so bunch of good worlds truly exist and a bunch of bad worlds don't?
Can if God found a possible world he liked exceptionally well, could he create it more that once so that he has many of it? Would that world be even more real than a world that was only created once?
Now consider just one of those possible worlds. Can we imagine the possibility of having that world not be picked - of not having God sprinkle his pixie dust on it? Can we imagine it being picked, having God's pixie dust sprinkled on it? Now how many possibilities have we considering here, one or two? Is a possible world with existence the same or different from an identical possible world without existence? If these are two different possiblities, could God be powerful enough to make both of these possiblities real at the same time? Does adding existence to a possible world do anything to change that world at all? If it doesn't, than what significance does the pixie dust have for the inhabitants of that world?
Lets also consider if God also had antipixiedust, that makes worlds instantly cease to exist. Is it possible for any world to have antipixiedust sprinked on it? How could a world with antipixiedust on it exist? If such a world can't exist, isn't that exactly the same thing as saying that it's not possible to have antipixiedust sprinkled on worlds? If god can't have antipixiedust or anything like it (since remember its just a placeholder for whatever means god might use to make a world not exist), maybe worlds exist that God is powerless to eliminate? What if our God is just a creation in a metauniverse created by a bigger supergod with a twisted sense of humor, and the supergod is creating universes our God can't get rid of just to annoy him?
If this is all too crazy for you to think about, take consolation in the fact that it's just a game played with empty words - e.g. with words that are poorly defined. It's a meaningless word game designed to confuse people or influence them emotionally. But realize that also includes WHAT YOU SAID. I am just extrapolating from what the "God created the universe" people started, and I am doing it solely for the point of illustrating how the statement lacks any firm foundation. What you said about God creating the universe is not even right or wrong - it's nonsensical from the start. It doesn't stand up to any significant philosophical analysis.
Now if you say the Peanuts universe came to be because Charles Schulz created it - I'd counter that what you really meant to say is that Schultz caused the fictional Peanuts universe to be part of our universe, using our physical ink and paper. If you are saying that we should believe in God because God made our universe part of his universe, how do we confirm that? Is there a way for us to look outside our universe to verify that it really is inside his? A claim one can't confirm can't form the basis of a persuasive argument.
How do the characters in a really awesome novel know if they are in last years New York times bestseller or if instead they are trapped in a story noone will ever think to write? How do they tell? If the characters in the story can't tell the difference, what makes you think we have any advantage over them? Maybe the unwritten story has no author and our uncreated universe has no creator?