The watchword of all well-being, of all moral good is not 'I' but 'Thou'. Who cares whether there is a heaven or a hell, who cares if there is a soul or not, who cares if there is an unchangeable or not? Here is the world, and it is full of misery. Go out into it as Buddha did, and struggle to lessen it or die in the attempt. Forget yourselves; this is the first lesson to be learnt, whether you are a theist or an atheist, whether you are an agnostic or a Vedantist, a Christian or a Mohammedan.