7 But neither do I demand that this should be said, or that I should be told what causes the gods have for their anger against men, that having taken offense they must be soothed. I do ask, however, Did they ever ordain any laws for mortals? And was it ever settled by them what it was fitting for them to do, or what it was not? What they should pursue, what avoid; or even by what means they wished themselves to be worshipped, so that they might pursue with the vengeance of their wrath what was done otherwise than they had commanded, and might be disposed, if treated contemptuously, to avenge themselves on the presumptuous and transgressors? As I think, nothing was ever either settled or ordained by them, since neither have they been seen, nor has it been possible for it to be discerned very clearly whether there are any. What justice is there, then, in the gods of heaven being angry for any reason with those to whom they have neither deigned at any time to show that they existed, nor given nor imposed any laws which they wished to be honoured by them and perfectly observed?
Source: Against the Heathen (New Advent)