Forgive your enemies, but never forget their names.

Too often we enjoy the comfort of opinion without the discomfort of thought.

The great enemy of the truth is very often not the lie — deliberate, contrived and dishonest — but the myth — persistent, persuasive, and unrealistic. Commencement address, Yale University, New Haven, Connecticut (11 June 1962)

The Chinese use two brush strokes to write the word 'crisis'. One brush stroke stands for danger; the other for opportunity. In a crisis, be aware of the danger, but recognize the opportunity. Speech in Indianapolis, April 12, 1959

The United States, as the world knows, will never start a war. We do not want a war. We do not now expect a war. This generation of Americans has already had enough — more than enough — of war and hate and oppression. We shall be prepared if others wish it. We shall be alert to try to stop it. But we shall also do our part to build a world of peace where the weak are safe and the strong are just. We are not helpless before that task or hopeless of its success. Address at The American University, Washington D.C. (10 June 1963)

If we cannot end now our differences, at least we can make the world safe for diversity. For, in the final analysis, our most basic common link is that we all inhabit this small planet. We all breathe the same air. We all cherish our children's future. And we are all mortal. Address at The American University, Washington D.C. (10 June 1963)

What kind of peace do we seek? Not a Pax Americana enforced on the world by American weapons of war. Not the peace of the grave or the security of the slave. I am talking about genuine peace, the kind of peace that makes life on earth worth living, the kind that enables men and nations to grow and to hope and to build a better life for their children — not merely peace for Americans but peace for all men and women — not merely peace in our time but peace for all time. Address at The American University, Washington D.C. (10 June 1963)

For of those to whom much is given, much is required. And when at some future date the high court of history sits in judgement on each of us, recording whether in our brief span of service we fulfilled our responsibilities to the state, our success or failure, in whatever office we hold, will be measured by the answers to four questions: First, were we truly men of courage… Second, were we truly men of judgement… Third, were we truly men of integrity… Finally were we truly men of dedication? Speech to Massacchussetts State Legislature (9 January 1961)

If by a "Liberal" they mean someone who looks ahead and not behind, someone who welcomes new ideas without rigid reactions, someone who cares about the welfare of the people — their health, their housing, their schools, their jobs, their civil rights, and their civil liberties — someone who believes we can break through the stalemate and suspicions that grip us in our policies abroad, if that is what they mean by a "Liberal," then I'm proud to say I'm a "Liberal." Acceptance of the New York Liberal Party nomination (14 September 1960)

Today, every inhabitant of this planet must contemplate the day when this planet may no longer be habitable. Every man, woman and child lives under a nuclear sword of Damocles, hanging by the slenderest of threads, capable of being cut at any moment by accident, or miscalculation, or by madness. The weapons of war must be abolished before they abolish us. In an address before the General Assembly of the United Nations on September 25, 1961.

The path we have chosen for the present is full of hazards, as all paths are; but it is one of the most consistent with our character and our courage as a nation and our commitments around the world. The cost of freedom is always high — but Americans have always paid it. And one path we shall never choose, and this is the path of surrender or submission. Our goal is not victory of might but the vindication of right — not peace at the expense of freedom, but both peace and freedom, here in this hemisphere and, we hope, around the world. God willing, that goal will be achieved. Thank you, and good night. Cuban Missile Crisis speech (22 October 1962)

Those who make peaceful revolution impossible will make violent revolution inevitable. Address to Latin American diplomats at the White House (12 March 1962)

In the long history of the world, only a few generations have been granted the role of defending freedom in its hour of maximum danger. I do not shrink from this responsibility — I welcome it. I do not believe that any of us would exchange places with any other people or any other generation. The energy, the faith, the devotion which we bring to this endeavor will light our country and all who serve it — and the glow from that fire can truly light the world.
And so, my fellow Americans: ask not what your country can do for you — ask what you can do for your country.
My fellow citizens of the world: ask not what America will do for you, but what together we can do for the freedom of man. Inaugural Address (20 January 1961)

With a good conscience our only sure reward, with history the final judge of our deeds, let us go forth to lead the land we love, asking His blessing and His help, but knowing that here on earth God's work must truly be our own. Inaugural Address (20 January 1961)

If a beachhead of cooperation may push back the jungle of suspicion, let both sides join in creating a new endeavor, not a new balance of power, but a new world of law, where the strong are just and the weak secure and the peace preserved.
All this will not be finished in the first one hundred days. Nor will it be finished in the first one thousand days, nor in the life of this Administration, nor even perhaps in our lifetime on this planet. But let us begin. Inaugural Address (20 January 1961)