Julian Baggini in The Guardian's Comment is free:
Herein contains what we might call the paradox of revelation, which is confronted by any organised religion that is based on revelation, in whole or part. As its meaning makes clear, you can't have a “revelation” that tells everyone what they already know. The supposed revelations of God to humanity through Christ, or the word of God to Mohammed through the angel Gabriel, had the power they did because they indicated new truths, new directions for followers.
However, having established a religion on those revelations, the teachings revealed through them become non-negotiable, and the ecclesiastical authorities become the arbiters of their interpretation. And so that means no further revelation is admissible if it contradicts what is already believed. Revelation of radical new truths, if accepted as real, thus makes future revelation of radical new truths impossible. To put it another way, what was absolutely valid for the establishing of a religion becomes by necessity invalid once it already exists.
This isn't trivial. Although the Catholic church exists to further God's will on earth, the criteria set out by the Sacred Congregation for the Doctrine of the Faith make it impossible for the church to accept God's will as being anything other than what they already believe. So while in theory entirely subservient to God's will, God's will actually turns out to be subservient to that of the church.
Read the rest here.