“Absolute liberty is absence of restraint; responsibility is restraint; therefore the ideally free individual is responsible only to himself.”

Source: Legal foundations of capitalism. 1924, p. 111

p, 125
Other writings, The Paradoxes of Legal Science (1928)

Reported in The Episcopalian: Volume 138 (1973), p. 12.

Post-Presidency, Nobel lecture (2002)
Context: The world has changed greatly since I left the White House. Now there is only one superpower, with unprecedented military and economic strength. The coming budget for American armaments will be greater than those of the next fifteen nations combined, and there are troops from the United States in many countries throughout the world. Our gross national economy exceeds that of the three countries that follow us, and our nation's voice most often prevails as decisions are made concerning trade, humanitarian assistance, and the allocation of global wealth. This dominant status is unlikely to change in our lifetimes.
Great American power and responsibility are not unprecedented, and have been used with restraint and great benefit in the past. We have not assumed that super strength guarantees super wisdom, and we have consistently reached out to the international community to ensure that our own power and influence are tempered by the best common judgment.
Within our country, ultimate decisions are made through democratic means, which tend to moderate radical or ill-advised proposals. Constrained and inspired by historic constitutional principles, our nation has endeavored for more than two hundred years to follow the now almost universal ideals of freedom, human rights, and justice for all.

International Liberal Conference (July 1928)
Later life

Oscar Iden Lecture Series, Lecture 3: "The State of Individuals" (1976)

Speech at the Charleston Bar Dinner (May 10, 1847); reported in Edward Everett, ed., The Works of Daniel Webster (1851), Vol. II, p. 393

Political Disquisitions (1774)
Context: That government only can be pronounced consistent with the design of all government, which allows to the governed the liberty of doing what, consistently with the general good, they may desire to do, and which only forbids their doing the contrary. Liberty does not exclude restraint; it only excludes unreasonable restraint. To determine precisely how far personal liberty is compatible with the general good, and of the propriety of social conduct in all cases, is a matter of great extent, and demands the united wisdom of a whole people. And the consent of the whole people, as far as it can be obtained, is indispensably necessary to every law, by which the whole people are to be bound; else the whole people are enslaved to the one, or the few, who frame the laws for them.

Vol. 1, Notes to the Chapters: Ch. 7, Note 4
The Open Society and Its Enemies (1945)
Context: The so-called paradox of freedom is the argument that freedom in the sense of absence of any constraining control must lead to very great restraint, since it makes the bully free to enslave the meek. The idea is, in a slightly different form, and with very different tendency, clearly expressed in Plato.
Less well known is the paradox of tolerance: Unlimited tolerance must lead to the disappearance of tolerance. If we extend unlimited tolerance even to those who are intolerant, if we are not prepared to defend a tolerant society against the onslaught of the intolerant, then the tolerant will be destroyed, and tolerance with them. — In this formulation, I do not imply, for instance, that we should always suppress the utterance of intolerant philosophies; as long as we can counter them by rational argument and keep them in check by public opinion, suppression would certainly be unwise. But we should claim the right to suppress them if necessary even by force; for it may easily turn out that they are not prepared to meet us on the level of rational argument, but begin by denouncing all argument; they may forbid their followers to listen to rational argument, because it is deceptive, and teach them to answer arguments by the use of their fists or pistols. We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant. We should claim that any movement preaching intolerance places itself outside the law, and we should consider incitement to intolerance and persecution as criminal, in the same way as we should consider incitement to murder, or to kidnapping, or to the revival of the slave trade, as criminal.