“He who passively accepts evil is as much involved in it as he who helps to perpetrate it.”

1950s, Three Ways of Meeting Oppression (1958)
Context: To accept passively an unjust system is to cooperate with that system; thereby the oppressed become as evil as the oppressor. Non-cooperation with evil is as much a moral obligation as is cooperation with good. The oppressed must never allow the conscience of the oppressor to slumber. Religion reminds every man that he is his brother's keeper. To accept injustice or segregation passively is to say to the oppressor that his actions are morally right. It is a way of allowing his conscience to fall asleep. At this moment the oppressed fails to be his brother's keeper. So acquiescence-while often the easier way-is not the moral way. It is the way of the coward.

"A River Runs Through It", p. 22
A River Runs Through It (1976)

2006

§ 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.

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.

Source: Brisingr

Maxim 139
Sentences

Source: Self-Help; with Illustrations of Character and Conduct (1859), Ch. I : Self-Help — National and Individual