Quintilian Inst Orat. 5.14
“In addition, the harsher something is by nature, the more it must be peppered with pleasures. A speech’s content is less suspicious thanks to disguise; and the audience’s pleasure aids much the speech’s credibility. Unless, of course, we believe that Cicero put it badly in his suggestion that “laws keep quiet among arms’ or “sometimes a sword is handed to us by the laws themselves.” In these cases, the devices must be consideration as an ornament, not an impediment.”
quoque quid est natura magis asperum, hoc pluribus condiendum est voluptatibus, et minus suspecta argumentatio dissimulatione, et multum ad fidem adiuvat audientis voluptas: nisi forte existimamus Ciceronem haec ipsa male in argumentatione dixisse, ‘silere leges inter arma’, et ‘gladium nobis interim ab ipsis porrigi legibus’. In his tamen habendus is est modus ut sint ornamento, non impedimento.