Every area of trouble gives out a ray of hope; and the one unchangeable certainty is that nothing is certain or unchangeable.

In a very real sense, it will not be one man going to the moon it will be an entire nation. For all of us must work to put him there.

Every inhabitant of this planet must contemplate the day when this planet may no longer be habitable .. The weapons of war must be abolished before they abolish us.

Truth is a tyrant-the only tyrant to whom we can give our allegiance. The service of truth is a matter of heroism.

There are those who regard this history of past strife and exile as better forgotten. But, to use the phrase of Yeats, let us not casually reduce "that great past to a trouble of fools." For we need not feel the bitterness of the past to discover its meaning for the present and the future.

Any system of government will work when everything is going well. It's the system that functions in the pinches that survive

There is, in addition to a courage with which men die; a courage by which men must live.