"If the spring of popular government in time of peace is virtue, the springs of popular government in revolution are at once virtue and terror: virtue, without which terror is fatal; terror, without which virtue is impotent. The terror is nothing other than justice, prompt, severe, inflexible; it is therefore an emanation of virtue; it is not so much a special principle as it is a consequence of the general principle of democracy applied to our country's most urgent needs."

Maximilien Robespierre, 'On the Principles of Political Morality', report to the National Convention, Paris, 5 February 1794. Delivered as the Reign of Terror was at its height.