The Prince on De Officiis: “Mr Burd points out that this passage is imitated directly from Cicero's "De Officiis": "Nam cum sint duo genera decertandi, unum per disceptationem, alterum per vim; cumque illud proprium sit hominis, hoc beluarum; confugiendum est ad posterius, si uti non licet superiore."”
Emile on De Officiis: “Conscience is the most enlightened philosopher; to be an honest man we need not read Cicero's De Officiis, and the most virtuous woman in the world is probably she who knows least about virtue.”