“The moral law was not written for men alone in their individual character, but it was written as well for nations, and for nations great as this of which we are citizens. If nations reject and deride that moral law, there is a penalty which will inevitably follow. It may not come at once, it may not come in our lifetime; but, rely upon it, the great Italian is not a poet only, but a prophet, when he says: "The sword of heaven is not in haste to smite, Nor yet doth linger."”

From Introductory Essay Specimens with Memoirs, 1860 edition
Other Quotes

2013, Brandenburg Gate Speech (June 2013)

Napoleon the Little (1852), Conclusion, Part Second, I
Napoleon the Little (1852)

Zen Masters : The Wisdom of Frank Zappa (2003)

Plato, 51.
The Lives and Opinions of Eminent Philosophers (c. 200 A.D.), Book 3: Plato

2009, Nobel Prize acceptance speech (December 2009)
Context: In today's wars, many more civilians are killed than soldiers; the seeds of future conflict are sown, economies are wrecked, civil societies torn asunder, refugees amassed, children scarred.
I do not bring with me today a definitive solution to the problems of war. What I do know is that meeting these challenges will require the same vision, hard work, and persistence of those men and women who acted so boldly decades ago. And it will require us to think in new ways about the notions of just war and the imperatives of a just peace.
We must begin by acknowledging the hard truth: We will not eradicate violent conflict in our lifetimes. There will be times when nations — acting individually or in concert — will find the use of force not only necessary but morally justified.
I make this statement mindful of what Martin Luther King Jr. said in this same ceremony years ago: "Violence never brings permanent peace. It solves no social problem: it merely creates new and more complicated ones." As someone who stands here as a direct consequence of Dr. King's life work, I am living testimony to the moral force of non-violence. I know there's nothing weak — nothing passive — nothing naïve — in the creed and lives of Gandhi and King.
But as a head of state sworn to protect and defend my nation, I cannot be guided by their examples alone. I face the world as it is, and cannot stand idle in the face of threats to the American people. For make no mistake: Evil does exist in the world. A non-violent movement could not have halted Hitler's armies. Negotiations cannot convince al Qaeda's leaders to lay down their arms. To say that force may sometimes be necessary is not a call to cynicism — it is a recognition of history; the imperfections of man and the limits of reason.

"Keep Moving from this Mountain" http://www5.spelman.edu/about_us/news/pdf/70622_messenger.pdf – Founders Day Address at the Sisters Chapel, Spelman College (11 April 1960)
1960s
Context: I think we have been in the mountain of moral and ethical relativism long enough. To dwell in this mountain has become something of a fad these days, so we have come to believe that morality is a matter of group consensus. We attempt to discover what is right by taking a sort of gallup poll of the majority opinion. Everybody is doing it, so it must be all right, and therefore we are caught in the clutches of conformity... In a sense, we are no longer concerned about the ten commandments-they are not too important. Everybody is busy, as I have said so often, trying to obey the eleventh commandment: “Thou shalt not get caught.” And so, according to this view, it is all right to lie with a bit of finesse. It’s all right to exploit, but be a dignified exploiter. It’s all right to even hate, but dress your hate up into garments of love and make it appear that you are loving when you are actually hating. This type of moral and ethical relativism is sapping the very life’s blood of the moral and spiritual life of our nation and our world. And I am convinced that if we are to be a great nation, and if we are to solve the problems of the world we must come out of this mountain. We have been in it too long. For if man fails to reorientate his life around moral and ethical values he may well destroy himself by the misuse of his own instrument.

Collected Works Vol. IV. Part 1 : Before the Face of God, Ch.1 : "On the History and Spirit of Carmel" http://www.karmel.at/ics/edith/stein_9.html
Context: What is meant by "the Law of the Lord"? Psalm 118 which we pray every Sunday and on solemnities at Prime, is entirely filled with the command to know the Law and to be led by it through life. The Psalmist was certainly thinking of the Law of the Old Covenant. Knowing it actually did require life-long study and fulfilling it, life-long exertion of the will. But the Lord has freed us from the yoke of this Law. We can consider the Savior's great commandment of love, which he says includes the whole Law and the Prophets, as the Law of the New Covenant. Perfect love of God and of neighbor can certainly be a subject worthy of an entire lifetime of meditation. But we understand the Law of the New Covenant, even better, to be the Lord himself, since he has in fact lived as an example for us of the life we should live. We thus fulfill our Rule when we hold the image of the Lord continually before our eyes in order to make ourselves like him. We can never finish studying the Gospels.

The Anatomy of the Nuremberg Trials: A Personal Memoir