So the law is holy, and the commandment is holy and righteous and good. Romans 7:12ESV
Question 92 of the Larger Catechism, asks, "What did God at first reveal unto man as the rule of his obedience?" It gives the answer, "The rule of obedience revealed to Adam in the estate of innocence, and to all mankind in him, besides a special command not to eat of the fruit of the tree of the knowledge of good and evil was the moral law." Last week we saw that our duty to God is obedience to His revealed will. This week we begin to examine the God given rule for our obedience: the moral law.
Man was created to obey God. There is a sense in which all of God's creatures were created for obedience. The dirt "obeys" God when it does exactly what dirt is supposed to do. It stays still on the ground unless disturbed. It supports those who walk on it. It becomes mud when it gets wet, etc. Likewise, dogs "obey" God by doing what dogs are supposed to do and not what monkeys, fish, or dandelions are supposed to do. In fact, every creature that acts exactly and only according to its nature can be said to "obey" God. However, we do not typically speak of "obedience" in this fashion. Obedience is the willful and deliberate act to conform to and comply with an expressed command or instruction. In this sense plants and animals do not "obey" God, they simply and automatically act according to their nature. The dandelion must be a dandelion. It does not have the ability or power to be, or to even desire to be, anything else. Among the earthly creatures, only man was given the ability to deliberately and willfully obey God. Thus, only man was created to truly obey God by consciously conforming himself to God's revealed will.
If man is to conform himself by a willful and therefore rational act to God's revealed will, then there must be some rule given by God to man that clearly teaches man how to obey Him. That rule is what theologians have called the moral law and it is often distinguished from the ceremonial and judicial law. The ceremonial law was given by God to symbolically anticipate the redemption accomplished by Christ. Hence, once Jesus Christ came the ceremonial law was abrogated (see Westminster Confession 19.3). Likewise, the judicial law was given to Israel as a theocratic nation and it too expired with the state of that people (see Westminster Confession 19-4). However, the moral law was given by God to man as a Covenant of Works, originally written not on tablets of stone but on man's heart, being part of man's nature and conscience. Thus, the moral law of God is built into the fiber of every human being. The knowledge of this law is seen in the basic understanding of right and wrong that is reflected in all peoples and in all cultures. Though corrupted, more or less, in individuals and in nations, still there are no persons or groups of people who are not moral, neither has there ever been.
Scripture acknowledges the moral law in the heart of every man in Romans 1:19, which declares of all men that "what may be known of God is manifest in them for God has shown it to them." Romans 1:32 concludes that this knowledge of God teaches man those things which God considers to be "worthy of death." Similarly, Romans 2 reveals that God's moral law in man's heart results in man judging or exonerating his own actions: "for when Gentiles, who do not have the law, by nature do the things in the law, these, although not having the law, are a law to themselves, who show the work of the law written in their hearts, their conscience also bearing witness, and between themselves their thoughts accusing or else excusing them," (verses 14-15). Thus, the moral law of God is germane to man's humanness.
It is worth noticing that in addition to the moral law of God written on the heart of every man as man, the Catechism mentions the "special command" to not eat of the tree of the knowledge of good and evil, which was given "besides" the moral law. This unique prohibition was not part of the moral law of God. It was not part of man's nature. It was something extra given purely to test man's obedience to God, a test that man failed. When he did, the moral law in his heart went from being that which exalted him above the other creatures to that which condemned him as a disobedient sinner against his Maker. Thus, the condemnatory aspect of the moral law was brought about, not by anything inherently in the law itself, but by the birth of evil in man. And so, as the Scripture at the head of this article declares, the law of God, according to its own nature, was and continues to be "holy and righteous and good." Praise God for His good law!