I do not wish to involve myself in too large a question, and to discuss the treatment of slaves, towards whom we Romans are excessively haughty, cruel, and insulting. But this is the kernel of my advice: Treat your inferiors as you would be treated by your betters. And as often as you reflect how much power you have over a slave, remember that your master has just as much power over you. “But I have no master,” you say. You are still young; perhaps you will have one. Do you not know at what age Hecuba entered captivity, or Croesus, or the mother of Darius, or Plato, or Diogenes?
Source: Lucius Annaeus Seneca. Moral Epistles. Translated by Richard M. Gummere. The Loeb Classical Library. Cambridge, Mass.: Harvard UP, 1917-25.