“No people on earth can be held, as a people, to be an enemy, for all humanity shares the common hunger for peace and fellowship and justice. … No nation's security and well-being can be lastingly achieved in isolation but only in effective cooperation with fellow-nations.”

Truman Library address (2006)
Context: No nation can make itself secure by seeking supremacy over all others. We all share responsibility for each other’s security, and only by working to make each other secure can we hope to achieve lasting security for ourselves.
— And, I would add that this responsibility is not simply a matter of States being ready to come to each other’s aid when attacked — important though that is. It also includes our shared responsibility to protect populations from genocide, war crimes, ethnic cleansing and crimes against humanity — a responsibility solemnly accepted by all nations at last year’s UN world summit. That means that respect for national sovereignty can no longer be used as a shield by Governments intent on massacring their own people, or as an excuse for the rest of us to do nothing when heinous crimes are committed.

This I Believe (1951)

1950s, Second Inaugural Address (1957)
Context: We look upon this shaken Earth, and we declare our firm and fixed purpose — the building of a peace with justice in a world where moral law prevails. The building of such a peace is a bold and solemn purpose. To proclaim it is easy. To serve it will be hard. And to attain it, we must be aware of its full meaning — and ready to pay its full price. We know clearly what we seek, and why. We seek peace, knowing that peace is the climate of freedom. And now, as in no other age, we seek it because we have been warned, by the power of modern weapons, that peace may be the only climate possible for human life itself. Yet this peace we seek cannot be born of fear alone: it must be rooted in the lives of nations. There must be justice, sensed and shared by all peoples, for, without justice the world can know only a tense and unstable truce. There must be law, steadily invoked and respected by all nations, for without law, the world promises only such meager justice as the pity of the strong upon the weak. But the law of which we speak, comprehending the values of freedom, affirms the equality of all nations, great and small. Splendid as can be the blessings of such a peace, high will be its cost: in toil patiently sustained, in help honorably given, in sacrifice calmly borne.

1910s, The New Nationalism (1910)
Context: I do not ask for overcentralization; but I do ask that we work in a spirit of broad and far-reaching nationalism when we work for what concerns our people as a whole. We are all Americans. Our common interests are as broad as the continent. I speak to you here in Kansas exactly as I would speak in New York or Georgia, for the most vital problems are those which affect us all alike. The national government belongs to the whole American people, and where the whole American people are interested, that interest can be guarded effectively only by the national government. The betterment which we seek must be accomplished, I believe, mainly through the national government.

2008, A World that Stands as One (July 2008)
Context: Partnership and cooperation among nations is not a choice; it is the one way, the only way, to protect our common security and advance our common humanity. That is why the greatest danger of all is to allow new walls to divide us from one another. The walls between old allies on either side of the Atlantic cannot stand. The walls between the countries with the most and those with the least cannot stand. The walls between races and tribes; natives and immigrants; Christian and Muslim and Jew cannot stand. These now are the walls we must tear down.

"Man In The News; A Traveler From Seoul: Roh Tae Woo" in The New York Times https://www.nytimes.com/1987/09/15/world/man-in-the-news-a-traveler-from-seoul-roh-tae-woo.html (15 September 1987)

Speech in Boston (2002)
Context: Israel will never get true security and safety through oppressing another people. A true peace can ultimately be built only on justice. We condemn the violence of suicide bombers, and we condemn the corruption of young minds taught hatred; but we also condemn the violence of military incursions in the occupied lands, and the inhumanity that won't let ambulances reach the injured.

Source: Speech to the National Union of Conservative and Constitutional Associations in St. James's Hall, London (15 May 1886), quoted in The Times (17 May 1886), p. 6

Foreword http://www.bartleby.com/55/100.html
1910s, Theodore Roosevelt — An Autobiography (1913)
Context: It seems to me that, for the nation as for the individual, what is most important is to insist on the vital need of combining certain sets of qualities, which separately are common enough, and, alas, useless enough. Practical efficiency is common, and lofty idealism not uncommon; it is the combination which is necessary, and the combination is rare. Love of peace is common among weak, short-sighted, timid, and lazy persons; and on the other hand courage is found among many men of evil temper and bad character. Neither quality shall by itself avail. Justice among the nations of mankind, and the uplifting of humanity, can be brought about only by those strong and daring men who with wisdom love peace, but who love righteousness more than peace.