As a vessel is known by the sound, whether it be whole or broken; so are men proved by their speech, whether they be wise or foolish.

First attributed to Demosthenes in the 1688 edition of N. Ling's Politeuphuia. Wits Common-wealth. | Compare Plato, Theaetetus 179d, Philebus 55c and Plutarch, How to Tell a Flatterer From a Friend 64d.