if there is a god, the question is where did god come from. if it was a big bang, the question is where did the matter involved in it come from. science has a decent reason to reason that there was some kind of origin event at least for the universe we currently know about, but some of those scientist at least entertain that something may have happened before this universe (by acknowledging that if anything did, it's impossible for us to observe it). god people say god is eternal. if you introduce anything that can be eternal, it seems like an ad hoc answer. x the creator is eternal. if that is possible, then so too is it possible the universe itself is eternal and there is no reason to make it any more complicated by suggesting there was a creation event. if we assume there must be a creation event for the universe, we can't break our own rule assuming an eternal creator. we must also ask where the creator came from. if we do not assume that everything had a creation event, we don't have either problem, but we'll still end up asking how or why everything exists.