A saying similar to this runs as follows: “Even if you have faith no bigger than a mustard seed, I tell you in truth that if you say to this mountain, Be moved into the sea — even that will be possible for you.” It seems to follow that anyone who is unable to move a mountain by following these directions is unworthy to be counted among the faithful. So there you are: not only the ordinary Christians, but even bishops and priests, find themselves excluded on the basis of such a saying.
Against the Christians, p. 51