Then, during the moral epoch of mankind, one sacrificed to one's god one's own strongest instincts, one's "nature": this festive joy lights up the cruel eyes of the ascetic, the "anti-natural" enthusiast.
Finally - what remained to be sacrificed? At long last, did one not have to sacrifice for once whatever is comforting, holy, healing; all hope, all faith in hidden harmony, in future blisses and justices? Didn't one have to sacrifice God himself and, from cruelty against oneself, worship the stone, stupidity, gravity, fate, the nothing? To sacrifice God for the nothing - this paradoxical mystery of the final cruelty was reserved for the generation that is now coming up: all of us already know something of this-
Thus Nietzsche, in Beyond Good and Evil, section 55.
I wonder to what extent this clarifies the death of God. It is not, in fact, a mere murder, but a cultic murder. God has not been merely killed, but sacrificed, in a final self-consuming act of religion. Again, it is to Nietzsche's credit that he recognises that this is a sacrifice. Of course, he thinks it will set humanity free in some sense, but it is nevertheless a suffering, a cruelty inflicted upon oneself which in some way forms the logical highpoint of asceticism (which Nietzsche considers to be the heart of religion).
The sacrifice of God plays out in different ways in the Christian tradition. The most basic statement that can be made about it is that God sacrifices himself - again, this is an event in the history of God, not merely a human event. Therefore the BCP can say of Christ's death that he "made there (by his one oblation of himself once offered) a full, perfect and sufficient sacrifice, oblation and satisfaction for the sins of the whole world". Perhaps the question to ask Nietzsche here is whether his own concept of the sacrifice of God is not merely an insufficient echo of the gospel.
More directly relevant, though, to Nietzsche's theme is the requirement that the gospel puts on Christians to be continually sacrificing God.
Now, before you think I've gone all Roman, I should say that I have in mind a mental process, and that strictly speaking I do not have in mind God. What I mean is this: the revelation of God in the gospel - in the face of Jesus Christ - teaches us that all of our ideas of God are wrong. Jesus Christ continually crashes through every symbol, doctrine, thought, image, or idea of God that I am able to devise. So I find myself in this position: I must have these symbols, doctrines, and ideas - without them I cannot think of God at all; but I am continually reminded that my symbols, doctrines, and ideas are inadequate - in fact, they are not truly representative of God.
So I am always sacrificing my image of God, always laying it on the altar - no matter how comforting or inspiring an image it is to me. I sacrifice it, to receive afresh the knowledge of God in the face of Jesus Christ. And as soon as that knowledge has passed into memory and symbol, I am called to sacrifice it.
Is there, then, nothing steady - nothing lasting - in the knowledge of God? Yes - but the steady, lasting thing is Jesus Christ himself, from whose grace my inadequate (and in itself idolatrous) knowledge of God can live.