Zacharius Ursinus was the primary author of our Heidelberg Catechism. He also wrote a sort of commentary (really, a series of lecture notes) on the Catechism, which are sorely neglected in our day. What follows are his comments on the Threefold Division of the Law (pp. 490-92), a Reformed manner of speaking about the way the Mosaic Law relates to Israel’s religious ceremonies and civil government and mankind’s morality.
On moral law
The moral law is a doctrine harmonising with the eternal and unchangeable wisdom and justice of God, distinguishing right from wrong, known by nature, engraven upon the hearts of creatures endowed with reason in their creation, and afterwards often repeated and declared by the voice of God through his servants, the prophets; teaching what God is and what he requires, binding all intelligent creatures to perfect obedience and conformity to the law, internal and external, promising the favor of God and eternal life to all those who render perfect obedience, and at the same time denouncing the wrath of God and everlasting punishment upon all those who do not render this obedience, unless remission of sins and reconciliation with God be secured for the sake of Christ the mediator.
On ceremonial laws
Ceremonial laws were those which God gave through Moses in reference to ceremonies, or the external solemn ordinances which were to be observed in the public worship of God, with a proper attention to the circumstances which had been prescribed; binding the Jewish nation to the coming of the Messiah, and at the same time distinguishing them from all other nations; and that they might also be signs, symbols, types and shadows of spiritual things to be fulfilled in the New Testament by Christ…
On civil (or “judicial”) laws
The judicial laws were those which had respect to the civil order or government, and the maintenance of external propriety among the Jewish people according to both tables of the Decalogue; or it may be said that they had respect to the order and duties of magistrates, the courts of justice, contracts, punishments, fixing the limits of kingdoms, etc. These laws God delivered through Moses for the establishment and preservation of the Jewish commonwealth, binding all the posterity of Abraham, and distinguishing them from the rest of mankind until the coming of the Messiah; and taht they might also serve as a bond for the preservation and government of the Mosaic polity, until the manifestation of the Son of God in the flesh, that they might be certain marks by which the nation which was bound by them, might be distinguished from all other nations, and might at the same time be the means of preserving proper discipline and order, that so they might be types of the order which should be established in the kingdom of Christ.
After articulating this division, Ursinus notes that moral laws are in a different category than the civil and ceremonial laws (pp. 492-93). The great difference is that all moral laws in Scripture are necessary consequences of the Decalogue, whereas ceremonial and civil laws cannot be deduced from the Decalogue necessarily. Ursinus finds the greatest difference in that “the moral law is known naturally, binds all men, and that perpetually; it is different, however, with the ceremonial and judicial law.” The ceremonial and civil have respect to external order and lead people to the moral law, which respects both externals and internals. The moral law can be called the goal of both the civil and the ceremonial. He even speaks of the Decalogue as “the renewal and re-enforcing of the natural law”, which is not the case with either ceremonial or civil laws.
Herein, Ursinus demonstrates why it is only the moral laws that remain binding upon Christians but only without the threatened curse. The other two have “been abrogated in as far as [they] relate to obedience.” This is because (1) the prophets foretold it (Dan. 9:27; Ps. 110:4), (2) the NT teaches it (Acts 7:8; 15:28-29; Heb. 7:11-18; 8:8-13), and (3) their various purposes are no longer (i.e., distinguishing them from the nations and serving as types of Christ).