A super super short version is about the question "how do you know X?" Its generally (although not universally) agreed that there are two types of knowledge, a priori and a posteriori. Roughly, in the first case, all you can deduce is implications from assumptions. For example, "if X and Y are true then Z is true." Such things don't require experience. The second case requires evidence gained from experience. Mathematical knowledge is of the first type, scientific knowledge is of the second type. The school of rationalism prioritizes the first type and the school of empericism emphasizes the second. That the universe was created by an omnipotent omniscient and benevolent god is not an emperical fact but requires some kind of a priori supports. Thats why you see so called proofs of god rather than scientific theories of god. There are other options of couree like mysticism, the claim that knowledge can be gained outside of these methods, or an emphasis on faith, that we don't take these things to be justifiable.
I probably butchered this but it gives you some starting points to research and hopefully shows a model of the debate. Huge topic. Check out https://plato.stanford.edu/entries/epistemology/ as a hardcore crashcourse or check "crash course philosophy" on youtube for the relavent sections at a more HS level. SEP has entries on god, faith and mysticism as well as rationalism and empericism too.