“Evil never goes unpunished, Monsieur. But the punishment is sometimes secret.”

1920s, The Reign of Law (1925)
Context: When the local government unit evades its responsibility in one direction, it is started in the vicious way of disregard of law and laxity of living. The police force which is administered on the assumption that the violation of some laws may be ignored has started toward demoralization. The community which approves such administration is making dangerous concessions. There is no use disguising the fact that as a nation our attitude toward the prevention and punishment of crime needs more serious attention. I read the other day a survey which showed that in proportion to population we have eight times as many murders as Great Britain, and five times as many as France. Murder rarely goes unpunished in Britain or France; here the reverse is true. The same survey reports many times as many burglaries in parts of America as in all England; and, whereas a very high percent of burglars in England are caught and punished, in parts of our country only a very low percent are finally punished. The comparison can not fail to be disturbing. The conclusion is inescapable that laxity of administration reacts upon public opinion, causing cynicism and loss of confidence in both law and its enforcement and therefore in its observance. The failure of local government has a demoralizing effect in every direction.

Lecture 7
Lectures on Education (1855)

Source: The Red Pyramid

Source: Sylvie and Bruno Concluded (1893), Chapter 19: A Fairy Duet

Chi non punisce il male comanda che si faccia.
The Notebooks of Leonardo da Vinci (1883), XIX Philosophical Maxims. Morals. Polemics and Speculations.
Variant: He who does not punish evil commands it to be done.

"A Plea For Intolerance" (1931)

"The Privilege of the Grave" (1905)
Context: As an active privilege, [free speech] ranks with the privilege of committing murder: we may exercise it if we are willing to take the consequences. Murder is forbidden both in form and in fact; free speech is granted in form but forbidden in fact. By the common estimate both are crimes, and are held in deep odium by all civilized peoples. Murder is sometimes punished, free speech always.

XIX. Why sinners are not punished at once.
On the Gods and the Cosmos
Context: It is not only spirits who punish the evil, the soul brings itself to judgment: and also it is not right for those who endure for ever to attain everything in a short time: and also, there is need of human virtue. If punishment followed instantly upon sin, men would act justly from fear and have no virtue.

Post-Presidency, Nobel lecture (2002)
Source: The Nobel Peace Prize Lecture