In plain words, ours
At the auction, asked what he was good at, he said: ruling people. Then he pointed at a man in a fine purple-bordered robe: sell me to him, he needs a master.
When the auctioneer asked in what he was proficient, he replied, In ruling men. Thereupon he pointed to a certain Corinthian with a fine purple border to his robe, the man named Xeniades above-mentioned, and said, Sell me to this man; he needs a master.
Diogenes Laertius, Lives of Eminent Philosophers 6.74Translated by R. D. Hicks (1925)Read the full passage (Diogenes Laertius, Lives of Eminent Philosophers 6.74, opens scaife.perseus.org)