“Blessed, unquestionably, is he who has it in his power to do evil, yet does it not.”

§ IV
1910s, At the Feet of the Master (1911)
Context: Superstition is another mighty evil, and has caused much terrible cruelty. The man who is a slave to it despises others who are wiser, tries to force them to do as he does. Think of the awful slaughter produced by the superstition that animals should be sacrificed, and by the still more cruel superstition that man needs flesh for food. Think of the treatment which superstition has meted out to the depressed classes in our beloved India, and see in that how this evil quality can breed heartless cruelty even among those who know the duty of brotherhood. Many crimes have men committed in the name of the God of Love, moved by this nightmare of superstition; be very careful therefore that no slightest trace of it remains in you.

Bk. III, ch. 11.
1840s, Past and Present (1843)

Wer den Daumen auf dem Beutel hat, der hat die Macht. <br class="br">Speech to North German Reichstag (21 May 1869), Stenographische Berichte p. 1017 (left) http://books.google.de/books?id=wm9HAAAAYAAJ&amp;pg=PA1017 <br class="br">1860s

Source: A Connecticut Yankee in King Arthur's Court (1889), Ch. 13.

Stephanie Parker, Chapter 9, p. 107
2000s, The Choice (2007)

Source: One-Dimensional Man (1964), p. 101

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.

Memoirs of J. Casanova de Seingalt (1894)