Thucydides (c. 460-400 BCE)
“He who thinks of his own pleasures and shrinks from fighting is very likely, because of his irresolution, to lose those very delights which caused his hesitation; while he who goes too far because of a success in war fails to realize that the confidence in which he goes forward is a hollow thing.”
- History of the Peloponnesian War (Book I, section 120) by Thucydides, translated by Rex Warner (Penguin Classics, 1972).