Thucydides (c. 460-400 BCE)
“To pay back a just debt by acting unjustly is more disgraceful than not to pay at all.”
- History of the Peloponnesian War (Book III, chapter 63) by Thucydides, translated by Rex Warner (Penguin Classics, 1972). The quote comes from a speech that Thucydides wrote while in the character of a Theban diplomat.