I like the 4e idea of gods as living concepts (possibly because of my IRL religion.)
So I like to think of the gods as sort of being BOTH "they came before there were ever creatures" and "they are the product of mortal actions." That is, the first is true in that the gods existed before there was any life to believe in them--they created that life. But once that life comes into being, it develops a symbiotic relationship (whether mutualistic or parasitic depends on a variety of factors) with those deities. Because mortal actions exemplify, instantiate, those concepts into the world.
IOW, when you do the right thing for the right reasons even when you don't have to, you are empowering Bahamut by doing so, though perhaps only in the smallest of ways. And when Bahamut reaches out and gives his blessing to a mortal, that encourages more mortals to be just and merciful and brave. Meanwhile, doing something petty and self-serving empowers Tiamat.
As above, so below; and as below, so above. We are not cosmic playthings, nor are the gods mere figments. We forge the world that will be, and thus the gods that will look upon it, by the actions we take.
So do not pay me in gold. Pay me with the prayer of works: show justice and mercy even to your bitterest enemy, be kind to every traveller who calls upon you for aid, hold fast to hope even in the darkest hour of the blackest night.