fields and houses and immediately received the care of their masters: Compare, Nepos, Atticus 13.4: He owned no slave who was not born and educated in his own house, which is a sign not only of his self restraint, but also of his diligence. For not to desire intemperately what you see to be desired by many ought to count as temperence, and to develop through diligence rather than to buy with money ought to be seen as a significant sign of industry.

Nepos' statement may be true, but it is certainly important as a statement of the sort of ideology appealed to here by Cassius.