Bartlett Jere Whiting expounds upon the proverb at length

B. J. Whiting, "The Nature of the Proverb," Harvard Studies and Notes in Philology 14 (1932) 302:

Brief excerpt only:

A proverb must be venerable; it must bear the sign of antiquity, and, since such signs may be counterfeited by a clever literary man, it should be attested in different places at different times. This last requirement we must often waive in dealing with very early literature, where the material at our disposal is incomplete.