Henry David Thoreau (2014). “Citizen Thoreau: Walden, Civil Disobedience, Life Without Principle, Slavery in Massachusetts, A Plea for Captain John Brown”, p.147, Graphic Arts Books
Speaking to the Roman Senate, as recorded by Sallust in The Catiline War (c. 40 b.c.). This quotation is a favorite of CIA counterintelligence officers.