Curse those greedy delvers! But what with? I know! How about Aurophobia, fear of gold? Or Barophobia, fear of gravity? And I can hit that annoying wizard with Bibliophobia, no more spells for him!
The TRUE origins of Magic, and dont even get me started on Prophecy.
A cult's theology is binding on the god involved: it is possible for that god to believe (and see, just like Winston Smith in 1984) that other gods are mythical, or jumped-up demons, or failing older spirits, even while those gods actually exist and thrive and act in the cosmos, even while working against him.