“Law. Law. That is what saves nations from the most imminent dangers.”

Reported as refuted in the Congressional Record: Lou Hiner, Jr., "Hitler's Phony Quotation on Law and Order", May 21, 1970, vol. 116, pp. 1676–77, reprinted from the Indianapolis News; and M. Stanton Evans, "The Hitler Quote", August 11, 1970, vol. 116, p. 28349, reprinted from the National Review Bulletin (August 18, 1970).
Misattributed

1960s, Memorial Day speech (1963)
Context: The law cannot save those who deny it but neither can the law serve any who do not use it. The history of injustice and inequality is a history of disuse of the law. Law has not failed — and is not failing. We as a nation have failed ourselves by not trusting the law and by not using the law to gain sooner the ends of justice which law alone serves. If the white over-estimates what he has done for the Negro without the law, the Negro may under-estimate what he is doing and can do for himself with the law.

Letter to Charles James Fox (8 October 1777)
1770s

1860s, "If Slavery Is Not Wrong, Nothing Is Wrong" (1864)
Context: Was it possible to lose the nation, and yet preserve the constitution? By general law life and limb must be protected; yet often a limb must be amputated to save a life; but a life is never wisely given to save a limb. I felt that measures, otherwise unconstitutional, might become lawful, by becoming indispensable to the preservation of the constitution, through the preservation of the nation. Right or wrong, I assumed this ground, and now avow it. I could not feel that, to the best of my ability, I had even tried to preserve the constitution, if, to save slavery, or any minor matter, I should permit the wreck of government, country, and Constitution all together.

Act III, scene i.
The Conspiracy and Tragedy of Charles, Duke of Byron (1608)

Inaugural Address Delivered to the University of St. Andrews, Feb. 1st 1867 (1867) p. 36. http://books.google.com/books?id=DFNAAAAAcAAJ&pg=PA36
Context: What is called the Law of Nations is not properly law, but a part of ethics: a set of moral rules, accepted as authoritative by civilized states. It is true that these rules neither are nor ought to be of eternal obligation, but do and must vary more or less from age to age, as the consciences of nations become more enlightened, and the exigences of political society undergo change. But the rules mostly were at their origin, and still are, an application of the maxims of honesty and humanity to the intercourse of states. They were introduced by the moral sentiments of mankind, or by their sense of the general interest, to mitigate the crimes and sufferings of a state of war, and to restrain governments and nations from unjust or dishonest conduct towards one another in time of peace. Since every country stands in numerous and various relations with the other countries of the world, and many, our own among the number, exercise actual authority over some of these, a knowledge of the established rules of international morality is essential to the duty of every nation, and therefore of every person in it who helps to make up the nation, and whose voice and feeling form a part of what is called public opinion. Let not any one pacify his conscience by the delusion that he can do no harm if he takes no part, and forms no opinion. Bad men need nothing more to compass their ends, than that good men should look on and do nothing. He is not a good man who, without a protest, allows wrong to be committed in his name, and with the means which he helps to supply, because he will not trouble himself to use his mind on the subject. It depends on the habit of attending to and looking into public transactions, and on the degree of information and solid judgment respecting them that exists in the community, whether the conduct of the nation as a nation, both within itself and towards others, shall be selfish, corrupt, and tyrannical, or rational and enlightened, just and noble.

28 May 1794
On the Impeachment of Warren Hastings (1788-1794)

The Anatomy of the Nuremberg Trials: A Personal Memoir

Letter to his son, Charles Carter Lee, as quoted in R.E.Lee: A Biography (1934) by Douglas Southall Freeman, Vol. I, p.32.