"True law is right reason in agreement with nature; it is of universal application, unchanging and everlasting; it summons to duty by its commands, and averts from wrong-doing by its prohibitions. And it does not lay its commands or prohibitions upon good men in vain, although neither have any effect on the wicked. It is a sin to try to alter this law, nor is it allowable to attempt to repeal a part of it, and it is impossible to abolish it entirely. We cannot be freed from its obligations by Senate or People, and we need not look outside ourselves for an expounder or interpreter of it. And there will not be different laws at Rome and at Athens, or different laws now and in the future, but one eternal and unchangeable law will be valid for all nations and all times, and there will be one master and ruler, that is, God, over us all, for He is the author of this law, its promulgator, and its enforcing judge. Whoever is disobedient is fleeing from himself and denying his human nature, and by reason of this very fact he will suffer the worst penalties, even if he escapes what is commonly called punishment ..."

-- Marcus Tullius Cicero, 59 - 47 B.C.
"Human law is law only by virtue of its accordance with right reason; and thus it is manifest that it flows from the eternal law. And in so far as it deviates from right reason it is called an unjust law; in such case it is no law at all, but rather a species of violence." 

-- Thomas Aquinas, Summa theologiae, Ia-Ilae, q. xciii, art. 3, ad 2m.
_"I acknowledge, in the ordinary course of government, that the exposition of the laws and Constitution devolves upon the judicial. But I beg to know upon what principle it can be contended that any one department draws from the Constitution greater powers than another in marking out the limits of the powers of the several departments."

-- James Madison, 1789