WCF 19: Of the Law of God

Unlike every other religion Christianity is fundamentally a message of grace. True believers are “not under the law, as a covenant of works, to be thereby justified or condemned” (cf. Rom. 6:14) Believers are saved by grace alone through faith alone in Christ alone.

But a misunderstanding of grace leads to a confused relationship with the law. Some think that any loyalty to law indicates legalism. Others ridicule God’s law, calling it inconsistent. After all, they reason, Old Testament prohibitions against homosexuality run alongside rules against mixing seeds in a field and materials in a garment (Lev. 18:22; 19:19; 20:13). Even Christians who are conscientious about God’s law can be unclear about which obligations are enduring and which have been fulfilled. We need a better understanding of God’s law so that we can use it in a way that honors him.

How Should I Understand God’s Law?

The principle of God’s law is very simple. The Creator imposes his values on his creatures. That truth never changes. In fact, in the New Testament Christ doubles-down on the necessity of rigorous obedience. In the Sermon on the Mount sincere submission to God’s law distinguishes citizens of God’s kingdom from citizens of the world. The law contrasts for us good works and works of the flesh. And we need that distinction. We must do good works which are only those “God hath commanded in his holy word” (16.1).

A right attitude toward God’s law requires understanding its history. The creation account reveals God’s right to order his creature’s activities. In the beginning God established boundaries for all of creation (Job 38:8–11). To his people he outlined definite expectations. You shall “fill the earth and subdue it” (Gen. 1:28). “You shall not eat” of the tree of the knowledge of good and evil (Gen. 2:17). He didn’t simply tell people to “be good,” whatever that means; he told us how to live.

Even after Adam and Eve violated the covenant of works God continued to require “personal, entire, exact, and perpetual obedience.”. In time God revealed himself more personally to a single tribe of people. When he rescued Israel from slavery in Egypt he made them into a holy nation by way of covenant, a binding agreement, summarized by the Ten Commandments (Ex. 19:6). And these laws are still “a perfect rule of righteousness.” If the two great commandments are to love God and our neighbor, these ten laws define that love (Matt 22:37–40). We love God by putting him first, worshiping him properly, respecting his name, and honoring his schedule for work and rest. We love our neighbor by respecting human authority, promoting life, practicing sexual integrity, stewarding our resources, telling the truth, and being content. 

So far so good. All serious Christians recognize ten commandments as a summary of God’s will. But what about the hundreds of other Old Testament laws? In addition to the abiding moral law God also gave Israel two categories of laws which do not apply to us today in the same way. The ceremonial laws told Israel how to worship and elaborated the moral laws in ways appropriate to their circumstances as a “church under age” (see Gal. 4:1–3). You don’t have to tell mature people to not touch the dials on a stove. Likewise, Spirit-filled believers have learned the principle of spiritual separation. The codes about mixed fabrics and seeds are unnecessary. Believers today know Christ. So we may not keep the old laws that required, for example, the sacrificial shedding of blood. When Christ came and poured out his Spirit on the church the old rules for worship became obsolete and the specific moral codes became unnecessary; they had done their job of teaching Old Testament people to anticipate the Messiah (Col. 2:14). Likewise the specific judicial or civil laws of Israel apply today only in establishing general principles—Kedesh is no longer a city of refuge for you if you commit manslaughter (Josh. 20:7–9). You are a citizen of a different country with different rules. But distinguishing between involuntary manslaughter and murder is still a necessary application of the sixth commandment.

Believers are not under law as a means of attaining righteousness. But Christ did not abolish the law (Matt. 5:17).

How Should I Use God’s Law?

God’s moral law is of “great use” to both believers and unbelievers.

Use God’s Law to Know How to Live

Moral opinions change from place to place and from age to age. Only God’s law consistently communicates his holy will. As “a rule of life” it reveals both his character and the corresponding duties we owe to him. The Bible is mainly the story of God’s redemption. But it also teaches us how we must live. The psalm-writer was correct in telling God, “You have commanded your precepts to be kept diligently” (Ps. 119:4). Paul agreed: “The law is holy, and the commandment is holy and righteous and good” (Rom. 7:12). Our inner beings should delight in it (Rom. 7:22). We are not like animals, left to operate at the level of instinct and urges. The sense of right and wrong that God has inscribed on our hearts (Rom. 2:15) he has also imprinted on the pages of his word.

Use God’s Law to Discover Your Sin

We desperately want to believe the best about ourselves. And with effort we can shrug off inner conviction. But it is harder to ignore God’s written word. Young King Josiah is an example for us. When he heard the words of the law “he tore his clothes” in humility; his “heart was penitent” (2 Kings 22:11, 19). Josiah knew that Judah was offending a holy God: “For great is the wrath of the Lord that is kindled against us” (2 Kings 22:13). Duly convicted he fought against idolatry with a holy hatred. And he believed God’s promise to pass-over the sin of the penitent. Josiah reinstituted the Passover which pointed to Christ and his perfect righteousness as the only protection against the angel of death. Use God’s law to come, as a needy sinner, to a perfect Savior

Use God’s Law to Resist Sin and Pursue Obedience

Believers should be stirred by a child-like reverence for God and an interest in doing whatever he commands. But God’s law provides additional motivation to obey. The law both defines obedience and assigns penalties for disobedience. The sin of believers cannot cancel God’s love for us—there is now no condemnation for those who are in Christ Jesus (Rom. 8:1). But our sin always brings consequences. By our sin we deliberately step outside of the circle of blessing that God promises to those who love him and keep his commandments. Truly God’s “perfect law” is “the law of liberty” (James 1:25). In keeping God’s rules “there is great reward” (Ps. 19:11). If you want to “love life and see good days,” resist sin and obey God’s law (1 Peter 3:10).

Grace is not opposed to law-keeping; grace is contrary to merit. For all our faithfulness we can earn nothing. Our best works come from the Spirit of Christ “subduing and enabling” our wills to freely and cheerfully obey God’s will. And the most loyal are still servants (Luke 17:10). But we are servants of a loving Creator. He pulls us out of a life of sin and certain destruction and summons us to walk with him on his terms. 

William Boekestein pastors Immanuel Fellowship Church in Kalamazoo, Michigan. He has authored numerous books including, with Joel Beeke, Contending for the Faith: The Story of The Westminster Assembly.


William Boekestein