About organized religionReligion is a form of controlling people: one man-machine wants to achieve power over another. Even the term "freedom," very often used by theologians, in its positive sense actually means "power." Religion is by no means more "fulfilling the will of God" than anything else. As God is primary and almighty, his will is by definition always fulfilled (it is impossible that he wills something and it is not fulfilled). A priest, a moralist does in fact nothing for man's "salvation," but just rules, and even when doing so he acts in a way that would (apart from that) be considered immoral.
Nietzsche goes on to analysing the Bible philologically and to guesses about the person of Jesus. He claims that it was not the aim of the latter to have anybody serve him, for God rules everything anyway; to the contrary, in Nietzsche's opinion Jesus fought with churchedness and the notion of sin rooted in the Old Testament. And thus in The Antichrist Christianity was portrayed as the corruption of the original doctrine taught by Jesus about equal rights of all to be children of God, the doctrine of no guilt and of no gulf between God and man.
The very "freedom of will" was invented by the priests in order to master the process of human thinking – and nothing more. And in order to master it, they had first to denaturize it.