"In Christianity neither morality nor religion come into contact with reality at any point. Nothing but imaginary causes ('God', 'soul', 'ego', 'spirit', 'freewill'- or 'unfree will'); nothing but imaginary effects ('sin', 'redemption', 'grace', 'punishment', 'forgiveness of sins'). A traffic between imaginary beings ('God', 'spirits', 'souls'); and imaginary natural science (anthropocentric; complete lack of understanding for natural causes); an imaginary psychology (nothing but self-misunderstandings, interpretations of pleasant or unpleasant general feelings...with the aid of the sign-language of religio-moral idiosyncrasy - 'repentance', 'sting of conscience', 'temptation by the Devil', 'the presence of God'); imaginary teleology ('the kingdom of God', 'the Last Judgement', 'eternal life').
This purely fictitious world is distinguished from the world of dreams, very much to its disadvantage, insofar as the latter mirrors actuality, while the former falsifies, disvalues, and denies reality. Once the concept 'nature' had been invented as the concept antithetical to 'God', 'natural' had to become 'reprehensible': this entire fictional world has its roots in the hatred of the natural (-reality!-), it is the expression of a profound discontent with the actual....
But that explains everything. Who alone has reason to lie himself out of reality? He who suffers from it. But to suffer from reality is to be an abortive reality.....The dominance of feelings of displeasure over feelings of pleasure is the cause of this fictitious morality and religion; but such dominance, however, provides the formula for decadence."
*Nietzsche, Friedrich. Twilight of the Idols/ The Anti-Christ. trans. R.J. Hollingdale. New York: Pengiun Books, 1985.
Although no interpretation of Nietzsche's ideas can be flawless, try these websites to enhance your understanding: Nietzsche