Diogenes Laertius (3rd Century Biographer of Philosophers)
“The virtue of the happy man and a well-running life consists in this: that all actions are based on the principle of harmony between his own spirit and the will of the director of the universe.”
- From Diogenes Laertius’ Lives of Eminent Philosophers (VII, 88), translated by M. Gigante, in Hellenistic Philosophy: Stoics, Epicureans, Skeptics edited by A. A. Long (University of California Press, 1986).