“We attacked a foreign people and treated them like rebels. As you know, it's all right to treat barbarians barbarically. It's the desire to be barbaric that makes governments call their enemies barbarians.”

to Domitian, Epp. Apoll. 21
Letters

Quoted in "Words of the wise: a book of Russian quotations" - 1979

Source: The Complete Essays

Magubane, Bernard M. (1996). The Making of a Racist State: British Imperialism and the Union of South Africa, 1875–1910. Trenton, New Jersey: Africa World Press. ISBN 978-0865432413.

As quoted in Human Development : A Science of Growth (1961) by Justin Pikunas, p. 311; this might be based on a translation or paraphrase by Viktor Frankl, to whom it is also sometimes attributed.
:In Wilhelm Meister’s Lehrjahre (Book VIII, Chapter four) Goethe writes:
:“Wenn wir” sagtest Du, “die Menschen nur nehmen, wie sie sind, so machen wir sie schlechter; wenn wir sie behandeln als wären sie, was sie sein sollten, so bringen wir sie dahin, wohin sie zu bringen sind."
:Werke, Hamburger Ausgabe in 14 Bänden, Verlag C. H. Beck München, Herausgegeben von Erich Trunz
: Variant translations:
:*Treat people as if they were what they ought to be and you help them to become what they are capable of being.
::* As quoted in My Country Vol. 2, No. 3 (September 1968) by Litchfield Historical Society, p. 23
:* "‘When we take people,’ thou wouldst say, ‘merely as they are, we make them worse; when we treat them as if they were what they should be, we improve them as far as they can be improved.’"
::* This translation occurs in the Harvard Classics edition of Wilhem Meister's Apprenticeship, Book VIII, Chapter IV. Translation by Thomas Carlyle Bartelby Online Edition of 'Wilhelm Meister's Apprenticeship'. http://www.bartleby.com/314/804.html
Disputed

On the Chinese government's policies towards Uighurs, the mainly Muslim minority living in Xinjiang in China's far west http://www.bbc.co.uk/news/blogs-china-blog-31018617 (7 May 2014)

Source: Rosencrantz and Guildenstern Are Dead

as cited by Grace Glueck, in 'Robert Motherwell, Master of Abstract, Dies', by Grace Glueck, 'New York Times, 18 July 1991 https://www.nytimes.com/1991/07/18/obituaries/robert-motherwell-master-of-abstract-dies.html
Undated