You are born into a dangerous world, there are all sorts of ways in which you could die, and you need to believe your parents when they tell you don't go near the edge of the cliff, or don't pick up that snake, etc. There could very well be a Darwinian survival value in that sort of brain rule of thumb. And a by-product of that could be that you believe your parents when they tell you about the juju in the sky, or whatever it might be.