Book 4 of 4 - External Means by which God Invites Us into the Society of Christ and Holds Us Therein
Chapter 20 - Civil Government
14-21 - Public law and judicial procedures
14. After the magistrate, now the law. Cicero said, "The law is a silent magistrate; the magistrate, a living law." Some say the laws have to follow "the political system of Moses, and... the common laws of nations" to be "duly framed," but this is absurd. The judicial laws are distinct from the moral law. It is true ceremonial and judicial laws touch on morals, but this doesn't require adherence to Mosaic judicial laws to be moral.
15. The moral law is summarized by loving God and neighbor. The ceremonial law was Jewish training in worship, "foreshadowing in figures" the coming fullness - Gal 4:3-4. The judicial law gave "formulas of equity and justice." Just as piety could continue with the abrogation of the ceremonial law, so justice and love to neighbor can continue without the exact form of the judicial law in Scripture. So laws today may "vary in form but [must] have the same purpose." Each nation is thus free to form its own laws.
16. All laws should work toward the same goal of equity. But there will be a diversity of punishments for various crimes, depending on the circumstances and dispositions of various countries. "How malicious and hateful toward public welfare would a man be who is offended by such diversity, which is perfectly adapted to maintain the observance of God's law?"