Libertas §9

⁹ What has been said of the liberty of individuals is no less applicable to them when considered as bound together in civil society. For, what reason and the natural law do for individuals, that human law , promulgated for their good, does for the citizens of States. Of the laws enacted by men, some are concerned with what is good or bad by its very nature; and they command men to follow after what is right and to shun what is wrong, adding at the same time a suitable sanction. But such laws by no means derive their origin from civil society, because, just as civil society did not create human nature, so neither can it be said to be the author of the good which befits human nature, or of the evil which is contrary to it. Laws come before men live together in society, and have their origin in the natural, and consequently in the eternal, law. The precepts, therefore, of the natural law, contained bodily in the laws of men, have not merely the force of human law, but they possess that higher and more august sanction which belongs to the law of nature and the eternal law. And within the sphere of this kind of laws the duty of the civil legislator is, mainly, to keep the community in obedience by the adoption of a common discipline and by putting restraint upon refractory and viciously inclined men, so that, deterred from evil, they may turn to what is good, or at any rate may avoid causing trouble and disturbance to the State. Now, there are other enactments of the civil authority, which do not follow directly, but somewhat remotely, from the natural law, and decide many points which the law of nature treats only in a general and indefinite way. For instance, though nature commands all to contribute to the public peace and prosperity, whatever belongs to the manner, and circumstances, and conditions under which such service is to be rendered must be determined by the wisdom of men and not by nature herself. It is in the constitution of these particular rules of life, suggested by reason and prudence, and put forth by competent authority, that human law, properly so called, consists, binding all citizens to work together for the attainment of the common end proposed to the community, and forbidding them to depart from this end, and, in so far as human law is in conformity with the dictates of nature, leading to what is good, and deterring from evil.