Chapter 15. He is greater than can be conceived. (Proslogium (Discourse on the existence of God)) (Anselm of Canterbury, St.)

Therefore, O Lord, you are not only that than which a greater cannot be conceived, but you are a being greater than can be conceived. For, since it can be conceived that there is such a being, if you are not this very being, a greater than you can be conceived. But this is impossible.