This Coetzee quotation (its from Elizabeth Costello) puts belief posterior to idea: 'Belief may be no more, in the end, than a source of energy, like a battery which one clips into an idea to make it run. As happens when one writes: believing whatever has to be believed in order to get the job done.'
It's striking, but I'm not sure it's quite right ... the implied separation of belief and idea, I mean: the implicit assertion that belief is something deeper than an idea, something in the bone, where ideas are how our minds articulate and manoeuvre their activity. I suppose I don't see how belief is, except as ideas. Belief is always a structure of thought, always a constellation of ideas, not a reservoir or energy. But maybe that's not right.