If I were a gambling man, I'd say that the odds are way better for the "a bloke made it up for shits/giggles/beer/women/money" than they are for "it was a supernatural omniscient omnipotent being, who's remained oddly silent on the big issues ever since".

I assume my dad (a very devout man) got what he needed when God decided to pop his aortic aneurism?

Mysterious ways, indeed.