Seneca,
Moral letters to Lucilius — Letter 41…
“ What, then, is such a soul? One which is resplendent with no external good, but only with its own. For what is more foolish than to praise in a man the qualities which come from without? And what is more insane than to marvel at characteristics which may at the next instant be passed on to someone else? A golden bit does not make a better horse. The lion with gilded mane, in process of being trained and forced by weariness to endure the decoration, is sent into the arena in quite a different way from the wild lion whose spirit is unbroken ”
