“In every government there are three sorts of power: the legislative; the executive in respect to things dependent on the law of nations; and the executive in regard to matters that depend on the civil law.
By virtue of the first, the prince or magistrate enacts temporary or perpetual laws, and amends or abrogates those that have been already enacted. By the second, he makes peace or war, sends or receives embassies, establishes the public security, and provides against invasions. By the third, he punishes criminals, or determines the disputes that arise between individuals. The latter we shall call the judiciary power, and the other, simply, the executive power of the state.
When the legislative and executive powers are united in the same person, or in the same body of magistrates, there can be no liberty; because apprehensions may arise, lest the same monarch or senate should enact tyrannical laws, to execute them in a tyrannical manner.
Again, there is no liberty if the judiciary power be not separated from the legislative and executive. Were it joined with the legislative, the life and liberty of the subject would be exposed to arbitrary control; for the judge would be then the legislator. Were it joined to the executive power, the judge might behave with violence and oppression.
There would be an end of every thing, were the same man, or the same body, whether of the nobles or of the people, to exercise those three powers, that of enacting laws, that of executing the public resolutions, and of trying the causes of individuals.
The executive power ought to be in the hands of a monarch, because this branch of government, having need of dispatch, is better administered by one than by many: on the other hand, whatever depends on the legislative power, is oftentimes better regulated by many than by a single person.
But, if there were no monarch, and the executive power should be committed to a certain number of persons, selected from the legislative body, there would be an end of liberty, by reason the two powers would be united; as the same persons would sometimes possess, and would be always able to possess, a share in both.”

ibid.
Books, articles, and speeches

Of Laws.
Political, Moral, and Miscellaneous Reflections (1750), Political Thoughts and Reflections

Order of Retaliation http://quod.lib.umich.edu/l/lincoln/lincoln6/1:755?rgn=div1;view=fulltext (30 July 1863); quoted in Roy P. Basler, ed., The Collected Works of Abraham Lincoln, vol. 7 (New Brunswick, N.J.: Rutgers University Press, 1953), p. 357
1860s
Context: It is the duty of every government to give protection to its citizens, of whatever class, color, or condition, and especially to those who are duly organized as soldiers in the public service. The law of nations and the usages and customs of war as carried on by civilized powers, permit no distinction as to color in the treatment of prisoners of war as public enemies. To sell or enslave any captured person, on account of his color, and for no offence against the laws of war, is a relapse into barbarism and a crime against the civilization of the age. The government of the United States will give the same protection to all its soldiers, and if the enemy shall sell or enslave anyone because of his color, the offense shall be punished by retaliation upon the enemy's prisoners in our possession. It is therefore ordered that for every soldier of the United States killed in violation of the laws of war, a rebel soldier shall be executed; and for every one enslaved by the enemy or sold into slavery, a rebel soldier shall be placed at hard labor on the public works and continued at such labor until the other shall be released and receive the treatment due to a prisoner of war

Source: The Reader

17 U.S. (4 Wheaton) 316, 415. Regarding the Necessary and Proper Clause in context of the powers of Congress.
McCulloch v. Maryland (1819)
Context: The subject is the execution of those great powers on which the welfare of a Nation essentially depends. It must have been the intention of those who gave these powers, to insure, as far as human prudence could insure, their beneficial execution. This could not be done by confiding the choice of means to such narrow limits as not to leave it in the power of Congress to adopt any which might be appropriate, and which were conducive to the end. This provision is made in a constitution intended to endure for ages to come, and, consequently, to be adapted to the various crises of human affairs.

Truman Library address (2006)
Context: Both security and development ultimately depend on respect for human rights and the rule of law.
— Although increasingly interdependent, our world continues to be divided — not only by economic differences, but also by religion and culture. That is not in itself a problem. Throughout history, human life has been enriched by diversity, and different communities have learnt from each other. But, if our different communities are to live together in peace we must stress also what unites us: our common humanity, and our shared belief that human dignity and rights should be protected by law.

John Grisham, The Last Juror: A Novel, p. 357 (Author's Note) (2004)
Source: [Grisham, John, 2004, The Last Juror, BCA, 357 (Author's Note), 0-385-51043-8]

Second Treatise of Civil Government, Ch. XII, sec. 143
Two Treatises of Government (1689)

The Architecture of Theories (1891)
Context: The origin of things, considered not as leading to anything, but in itself, contains the idea of First, the end of things that of Second, the process mediating between them that of Third. A philosophy which emphasises the idea of the One, is generally a dualistic philosophy in which the conception of Second receives exaggerated attention: for this One (though of course involving the idea of First) is always the other of a manifold which is not one. The idea of the Many, because variety is arbitrariness and arbitrariness is repudiation of any Secondness, has for its principal component the conception of First. In psychology Feeling is First, Sense of reaction Second, General conception Third, or mediation. In biology, the idea of arbitrary sporting is First, heredity is Second, the process whereby the accidental characters become fixed is Third. Chance is First, Law is Second, the tendency to take habits is Third. Mind is First, Matter is Second, Evolution is Third.