When one gives up the Christian faith, one pulls the right to Christian morality out from under one's feet... Christianity is a system, a whole view of things thought out together. By breaking one main concept out of it, the faith in God, one breaks the whole: nothing necessary remains in one's hands. Christianity presupposes that man does not know, cannot know, what is good for him, what evil: he believes in God, who alone knows it... it has truth only if God is the truth — it stands and falls with faith in God.

Friedrich Nietzsche