Diogenes Laërtius on Slavery

“To Xeniades, who had purchased Diogenes at the slave market, he said, "Come, see that you obey orders."”

“When some one boasted that at the Pythian games he had vanquished men, Diogenes replied, "Nay, I defeat men, you defeat slaves."”

“Once Diogenes, who was washing vegetables, ridiculed him as he passed by, and said, "If you had learnt to eat these vegetables, you would not have been a slave in the palace of a tyrant." But Aristippus replied, "And you, if you had known how to behave among men, would not have been washing vegetables."”