“Le loup sait bien ce que male bête pense ” [male =
méchant]. “Un fripon reconnait un fripon au premier coup d'oeil.” We judge others by ourselves. “Chacun mesure tout à son aune.” We measure others in our own bushel. The wolf believes that every
beast entertains the same wolfish thoughts and desires as it does
itself. Plautus expresses the same idea thus “Insanire me aiunt
ultro cum ipsi insanrunt;” and Cicero says, “Malum conscientia
suspiciosum facit”
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
