"Whenever we see that phrase, we may be almost certain that somebody has told the truth about somebody else."

Found (mostly) via http://chesterton.wordpress.com :-)
But Mr. Edwardes disposes finally of his own case in this respect by saying that the Westminster Gazette criticism was obviously inspired by malice and spite. Now this is a smashing test; this is always the thing that people say when they have literally nothing else to say. If a critic tells a particular lie, that particular lie can be pointed out. If he misses a specific point, that point can be explained. If he is really wrong in this or that, it will be on this or that that the insulted person will eagerly pounce. But “malice and spite” are vague words which will never be used except when there is really nothing to pounce on. If a man says that I am a dwarf, I can invite him to measure me. If he says I am a cannibal, I can invite him to dinner. If he says I am a coward, I can hit him. If he says I am a miser, I can give him half-a-sovereign. But if he says I am fat and lazy (which is true), the best I can answer is that he speaks out of malice and spite. Whenever we see that phrase, we may be almost certain that somebody has told the truth about somebody else.

-November 13, 1909, Illustrated London News