“We must not disguise from ourselves that we go to found a city among strangers and enemies, and he who undertakes such an enterprise should be prepared to become master of the country the first day he lands, or failing in this find everything hostile to him.”
Book VI, 6.23-[2]
History of the Peloponnesian War, Book VI
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Thucydides 76
Greek historian and Athenian generalRelated quotes

1960s, Inaugural address (1965)
Context: We aspire to nothing that belongs to others. We seek no dominion over our fellow man, but man's dominion over tyranny and misery. But more is required. Men want to be a part of a common enterprise—a cause greater than themselves. Each of us must find a way to advance the purpose of the Nation, thus finding new purpose for ourselves. Without this, we shall become a nation of strangers.

Quotes from his operas, Die Meistersinger von Nürnberg, Hans Sachs, Act 2, Scene 4
Original: (de) Mein Kind, für den ist alles verloren,
und Meister wird der in keinem Land;
denn wer als Meister geboren,
der hat unter Meistern den schlimmsten Stand.
Book 3, § 18.
Life of Apollonius of Tyana

Turkish Wikipedia
https://quotestats.com/topic/attila-hun-quotes/

(J. Hudson Taylor. A Ribband of Blue and Other Bible Studies. London: China Inland Mission, n.d., 94).
“We had been friends. We could not become strangers. It left only one thing: we must be enemies.”
The Prince in Waiting