The Saint is a medicine because he is an antidote. Indeed that is why the saint is often a martyr; he is mistaken for a poison because he is an antidote. He will generally be found restoring the world to sanity by exaggerating whatever the world neglects, which is by no means always the same element in every age. Yet each generation seeks its saint by instinct; and he is not what the people want, but rather what the people need.
This is surely the very much mistaken meaning of those words to the first saints, “Ye are the salt of the earth,” which caused the Ex-Kaiser to remark with all solemnity that his beefy Germans were the salt of the earth; meaning thereby merely that they were the earth’s beefiest and therefore best. But salt seasons and preserves beef, not because it is like beef; but because it is very unlike it. Christ did not tell his apostles that they were only the excellent people, or the only excellent people, but that they were the exceptional people; the permanently incongruous and incompatible people; and the text about the salt of the earth is really as sharp and shrewd and tart as the taste of salt. It is because they were the exceptional people, that they must not lose their exceptional quality. “If salt lose its savour, wherewith shall it be salted?” is a much more pointed question than any mere lament over the price of the best beef. If the world grows too worldly, it can be rebuked by the Church; but if the Church grows too worldly, it cannot be adequately rebuked for worldliness by the world.
— G. K. Chesterton