“I pondered all these things, and how men fight and lose the battle, and the thing that they fought for comes about in spite of their defeat, and when it comes turns out not to be what they meant, and other men have to fight for what they meant under another name.”

This statement is usually attributed entirely to Melville, but the way he presents it in the story indicates that he might be quoting a lesser known author.
Source: Billy Budd, the Sailor (1891), Ch. 21

Source: The Crossing

Selected Readings from the Works of Mao Tse-Tung, pp. 121
On Contradiction (1937)
Original: (zh-CN) 一切矛盾着的东西，互相联系着，不但在一定条件之下共处于一个统一体中，而且在一定条件之下互相转化，这就是矛盾的同一性的全部意义。列宁所谓“怎样成为同一的（怎样变成同一的），——在怎样的条件之下它们互相转化，成为同一的”，就是这个意思。

The Saviors of God (1923)
Context: My prayer is not the whimpering of a beggar nor a confession of love. Nor is it the petty reckoning of a small tradesman: Give me and I shall give you.
My prayer is the report of a soldier to his general: This is what I did today, this is how I fought to save the entire battle in my own sector, these are the obstacles I encountered, this is how I plan to fight tomorrow.

As quoted in Honor Your Gifts (2007) by Dona M. Deane, p. 199.
Variant: But there is suffering in life, and there are defeats. No one can avoid them. But it's better to lose some of the battles in the struggles for your dreams than to be defeated without ever knowing what you're fighting for

Anastacia: Speaks frankly about her new body, finding love again and using her voice to inspire other http://www.anastacia.com/hello-magazine/, Hello Magazine, April 14, 2014.
General Quotes

1850s, The Present Aspect of the Slavery Question (1859)
Context: The principle of our Revolution, as defined by its leaders with sublime simplicity, was, that as Liberty is a natural right of man, every man has consequent equal rights in society, subject indeed to limitation, but not to annihilation. 'But', cries Mister Douglas, in his Memphis speech last November. I quote his words,. It would have been very easy to say this. Our fathers did not say it, because they did not mean it. They were men who meant what they said, and who said what they meant, and meaning all men, they said all men. They were patriots asserting a principle and ready to die for it, not politicians pettifogging for the presidency.

Manuscript Found in Accra (2012), The Defeated Ones

Book Three, Part I “Snake’s Road”, Chapter 3 (p. 333)
The Birthgrave (1975)