Letters 47.11

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.

Seneca, Letters to Lucilius 47.11, translated by Richard Mott Gummere