Aristotle (c. 384-322 BCE)
“Virtue lies in our power, and similarly so does vice; because where it is in our powers to act, it is also in our power not to act, and where we can refuse we can also comply.”
- From The Nicomachean Ethics (Bekker number 1113b) by Aristotle, translated by J. A. K. Thomson (Penguin Classics, 2004).