Quintilian, Inst. Orat. 10.1.24-26
“Let the reader not be persuaded as a matter of course that everything the best authors said is perfect. For they slip at times, they give in to their burdens, and they delight in the pleasure of their own abilities. They do not always pay attention; and they often grow tired. Demosthenes seems to doze to Cicero; Homer naps for Horace. Truly, they are great, but they are still mortals and it happens that those who believe that whatever appears in these authors should be laws for speaking often imitate their lesser parts, since this is easier—and they believe they are enough like them if they emulate the faults of great authors.
Still, one must pass judgment on these men with modesty and care to avoid what often happens when people condemn what they do not understand. If it is necessary to err in either part, I would prefer readers to enjoy everything in these authors rather than dismiss much.”
Neque id statim legenti persuasum sit, omnia quae summi auctores dixerint utique esse perfecta. Nam et labuntur aliquando et oneri cedunt et indulgent ingeniorum suorum voluptati, nec semper intendunt animum, nonnumquam fatigantur, cum Ciceroni dormitare interim Demosthenes, Horatio vero etiam Homerus ipse videatur. Summi enim sunt, homines tamen, acciditque iis qui quidquid apud illos reppererunt dicendi legem putant ut deteriora imitentur (id enim est facilius), ac se abunde similes putent si vitia magnorum consequantur. Modesto tamen et circumspecto iudicio de tantis viris pronuntiandum est, ne, quod plerisque accidit, damnent quae non intellegunt. Ac si necesse est in alteram errare partem, omnia eorum legentibus placere quam multa displicere maluerim.