“Has it never occurred to us, when surrounded by sorrows, that they may be sent to us only for our instruction, as we darken the cages of birds when we wish to teach them to sing?”

2013, "Let Freedom Ring" Ceremony (August 2013)
Context: The March on Washington teaches us that we are not trapped by the mistakes of history; that we are masters of our fate. But it also teaches us that the promise of this nation will only be kept when we work together. We’ll have to reignite the embers of empathy and fellow feeling, the coalition of conscience that found expression in this place 50 years ago. And I believe that spirit is there, that truth force inside each of us. I see it when a white mother recognizes her own daughter in the face of a poor black child. I see it when the black youth thinks of his own grandfather in the dignified steps of an elderly white man. It’s there when the native-born recognizing that striving spirit of the new immigrant; when the interracial couple connects the pain of a gay couple who are discriminated against and understands it as their own. That’s where courage comes from -- when we turn not from each other, or on each other, but towards one another, and we find that we do not walk alone. That’s where courage comes from.

Standing by Words: Essays (2011), Poetry and Marriage: The Use of Old Forms (1982)

Source: My Utmost for His Highest: Traditional Updated Edition

Source: I Know Why the Caged Bird Sings

Source: Foucault's Pendulum

Early Writings, translated and ed. by , p. 159. https://www.marxists.org/archive/marx/works/1844/epm/3rd.htm
Context: Private property has made us so stupid and one-sided that an object is only ours when we have it, when it exists for us as capital or when we directly possess, eat, drink, wear, inhabit it, etc., in short, when we use it. Although private property conceives all these immediate realizations of possession only as means of life; and the life they serve is the life of private property, labor, and capitalization. Therefore all the physical and intellectual senses have been replaced by the simple estrangement of all these senses – the sense of having. So that it might give birth to its inner wealth, human nature had to be reduced to this absolute poverty.

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 71.

Letter to http://memory.loc.gov/cgi-bin/query/r?ammem/mtj:@field(DOCID+@lit(tj110158)) Thomas Leiper (12 June 1815). Published in The Works of Thomas Jefferson in Twelve Volumes http://oll.libertyfund.org/ToC/0054.php, Federal Edition, Paul Leicester Ford, ed., New York: G. P. Putnam's Sons, 1904, Vol. 11 http://oll.libertyfund.org/Texts/Jefferson0136/Works/0054-11_Bk.pdf, pp. 477–478.
The sentence "I hope our wisdom will grow with our power, and teach us, that the less we use our power, the greater it will be." was used by US-President Barack Obama in his A New Beginning Speech.
1810s
Context: We concur in considering the government of England as totally without morality, insolent beyond bearing, inflated with vanity and ambition, aiming at the exclusive dominion of the sea, lost in corruption, of deep-rooted hatred towards us, hostile to liberty wherever it endeavors to show its head, and the eternal disturber of the peace of the world. In our estimate of Bonaparte, I suspect we differ. [... ] Our form of government is odious to him, as a standing contrast between republican and despotic rule; and as much from that hatred, as from ignorance in political economy, he had excluded intercourse between us and his people, by prohibiting the only articles they wanted from us, that is, cotton and tobacco. Whether the war we have had with England, and the achievements of that war, and the hope that we may become his instruments and partisans against that enemy, may induce him, in future, to tolerate our commercial intercourse with his people, is still to be seen. For my part, I wish that all nations may recover and retain their independence; that those which are overgrown may not advance beyond safe measures of power, that a salutary balance may be ever maintained among nations, and that our peace, commerce, and friendship, may be sought and cultivated by all. It is our business to manufacture for ourselves whatever we can, to keep our markets open for what we can spare or want; and the less we have to do with the amities or enmities of Europe, the better. Not in our day, but at no distant one, we may shake a rod over the heads of all, which may make the stoutest of them tremble. But I hope our wisdom will grow with our power, and teach us, that the less we use our power, the greater it will be.

Source: One Crazy Summer