Styx is confusing the angry god of the Old Testament with the triune God of the New Testament. The jealous god of the Old Testament is a local mountain deity who made a black pact with the Hebrews -- he agreed to help them if they gave him all their worship, and didn't worship other gods. There was no question at that time that countless other gods existed. The idea that monotheism existed in the Old Testament books is a joke. Nobody believed that, not even the angry, jealous god of the mountain that Moses made his deal with.