Now we know that the law is good, if one uses it lawfully
— 1 Timothy 1:8 —
In his classic Systematic Theology, Louis Berkhof outlines three uses of the law,
[The Civil Use of the Law]
The law serves the purpose of restraining sin and promoting righteousness. Considered from this point of view, the law presupposes sin and is necessary on account of sin. It serves the purpose of God’s common grace in the world at large. This means that from this point of view it cannot be regarded a means of grace in the technical sense of the word.
[The Pedagogical Use of the Law]
In this capacity the law serves the purpose of bringing man under conviction of sin, and of making him conscious of his inability to meet the demands of the law. In that way the law becomes his tutor to lead him unto Christ, and thus becomes subservient to God’s gracious purpose of redemption.
[The Normative or Christian Use of the Law]
This is the so-called . . . the third use of the law. The law is a rule of life for believers, reminding them of their duties and leading them in the way of life and salvation. This third use of the law is denied by the Antinomians. (Berkhof, Systematic Theology, 614–615)
Not to be confused with the tripartite division of the Law (i.e., the Moral, Civil, Ceremonial), the three uses of the law are a traditional way Reformed (and other) theologians have explained law and its various uses in God’s plan of salvation.
Observing the way the New Testament, but especially Paul, spoke of the Law positively (Rom. 7:12; 1 Tim. 1:8) and negatively (Rom. 7:5–6; 8:2), this threefold approach shows how God’s law preserved the world from sin (first use), revealed sin and prepared Israel for the gospel (second use), and now continues to purify the Christian by means of Spirit-powered obedience to God’s law (third use). To better understand each aspect of the law, let’s consider each in turn.
Restraining Sin: The First Use of the Law
When God gave Moses the Law at Sinai, it had—or was meant to have—an immediate impact on the people redeemed from Egypt. This might be called the civil use of the law, and it is most evident in the specific stipulations of Exodus 21–23, Leviticus, and Deuteronomy.
Expounding the Decalogue (“Ten Words”), these national rules were given to establish a community of righteousness and compassion. A careful study of these commandments demonstrates how God sought to cultivate his own character in his people. The question is, “Was it effective? “
In a word, the answer is “no.” You can take Israel out of Egypt, but you cannot take Egypt out of Israel. For 400 years, Israel imbibed the morality and worldview of their captors, and thus they failed within days of receiving the Ten Commandments. In making the Golden Calf (Exodus 32), the people showed their inability to keep the Law. While redeemed by God and set apart as a holy nation (Exodus 19:4–6), the legal restraints would not be effective in producing ongoing righteousness.
The Law would be effective in creating a people from whom the Messiah would come, but their righteousness was never sustained. In their best days, when priests and kings led the nation according the prophetic word of Moses, glimpses of righteousness could be seen in Israel. But on the whole, the restraining nature of the law was always short-lived.
Thus, Paul can say “the law is holy, and the commandment is holy and righteous and good” (Romans 7:12), but he must also admit that the law increased sin (Romans 5:20) and could not give life (Romans 8:2). The reason, however, is not the unholiness of the Law, but the weakness of the flesh (Romans 8:3). While commanding righteousness, men and women dead in sin could not keep the Law. Therefore, we see a second purpose in the Law, and one on which the New Testament puts primary stress.
Revealing Sin: The Second Use of the Law
If the first use of the Law aimed to restrain sin and restrict its effects (see e.g., Deuteronomy 24:1–4), the second use of the Law sought to increase transgression—or at least, increase the people’s awareness of their inherent sinfulness. As Paul says in Romans 3:19–20,
Now we know that whatever the law says it speaks to those who are under the law, so that every mouth may be stopped, and the whole world may be held accountable to God. For by works of the law no human being will be justified in his sight, since through the law comes knowledge of sin.
That last statement is one that finds repetition in Paul’s letters. In Romans 7:7, for instance, Paul explains
What then shall we say? That the law is sin? By no means! Yet if it had not been for the law, I would not have known sin. For I would not have known what it is to covet if the law had not said, “You shall not covet.”
Likewise, Romans 4:15 says that “where there is no law there is no transgression” (cf. Romans 5:13). In the context of Romans, Paul is not denying sin in nations ignorant of Israel’s Law. The first three chapters make the point: those without the law (Gentiles) and those with the Law (Jews) are equally unrighteous before God (Romans 3:10–23). Paul’s point is the Law revealed to Moses is what makes sinful people know their sin.
Because of our sinful condition, we cannot even see our unrighteous condition. But under the light of the law, we begin to see our need. The Law teaches us of sin and the wrath of God. Yet, even more Paul says it stirs up sin within us.
Though we may appear to have hearts full of clean water, the Law stirs up the deadly sludge at the bottom of hearts. As Romans 7:8 says, “But sin, seizing an opportunity through the commandment, produced in me all kinds of covetousness. For apart from the law, sin lies dead.”
This is the second use of the Law and perhaps the most important aspect of the Law—it unveils our sin and our need for a Savior. In fact, built into this aspect of the Law is the gracious provision of a Savior. Because the Law of Moses was added to the promise (Galatians 3:17), it contains gracious promises of salvation within it. Yes, it makes legal demands, but it also magnifies the promise of grace. And this is why, Paul can say of the Law—it was a placeholder and a pedagogue (a tutor) that leads us to Christ (Galatians 3:19–24).
In the Old Testament, like the New, the way of salvation was always justification by faith (see Genesis 15:6). The Law did not change this way of salvation. Rather, it made more certain Israel’s need for grace. Paul emphasizes this aspect of the Law, so that the elect—whether Jews or Greeks—would come to a saving knowledge of God. This summarizes the second use of the Law, which in conjunction with the gospel creates Christians who are ready to be instructed by the Law in its third use.
Christian Instruction and Sanctification: The Third Use of the Law
Romans 10:4 says, Christ is the telos (end, goal) of the Law. This verse teaches how the Law was always given with the prophetic goal of getting to Jesus. The logic of 1 Timothy 1:8–11 echoes this idea—to read the law lawfully is to read it in concert with the gospel. The good news of the law is the way it leads to the gospel and the message that God is both just and justifier of those who have faith in Christ (Romans 3:23–30).
Because Jesus is the perfect embodiment of the Law, we can see how it trained him to be the perfect Psalm 1 man. It was also given to us to explain what God’s holy character in human form looks like. Indeed, the law is a shadow of Christ, and when read in faith, the law fulfilled in Christ has an instructive and sanctifying effect on the Christian.
While the new covenant believer is set free from the curses of the Law (Galatians 3:10–14), the Law—indeed, the whole Old Testament—is useful for instruction, reproof, correction, and training in righteousness (2 Timothy 3:16). For this reason, the Christian does not dismiss the Law of Moses, but reads it gladly watching how it reveals the character of God and displays the holy perfections of Christ.
Thankfully, Christians do not find their righteousness through the forms of Israel’s religion. But we do learn who Christ is and how to love others from Israel’s Law. As Paul says, love is the fulfillment of the law (Romans 13:8). Therefore, our love for God and others is sanctified as we read the Law. This is the third use of the law. As John Calvin puts it,
The third and principal use, which pertains more closely to the proper purpose of the law, finds its place among believers in whose hearts the Spirit of God already lives and reigns. For even though they have the law written and engraved upon their hearts by the finger of God [Jer. 31:33; Heb. 10:16], that is, have been so moved and quickened through the directing of the Spirit that they long to obey God, they still profit by the law in two ways. (Calvin, Institutes of the Christian Religion, 1:360)
Until we are glorified, God is sanctifying his people. And much of that sanctification is brought about by God’s Law—understood in this third sense. As the new covenant writes the law on our hearts (Jeremiah 31:33), it is the believers’ joy to do the will of his Father. No longer does the law taste like vinegar; no longer are we powerless to resist idol lusts. Made alive by God’s Spirit, the Law is now honey in our mouth and treasure in our heart (Psalm 19:10–11). Doing God’s will is no longer burdensome (1 John 5:3), but the underlying desire of our souls.
This does not deny the spiritual warfare that we experience (Ephesians 6:10–19), nor the inner tension we feel (Galatians 5:16–26), but alive in Christ God’s Law is no longer an enemy but a friend. As Psalm 119 exults, we love the testimonies of God because of what they tell us about our God. Moreover, with the mind of Christ (1 Corinthians 2:10–16), we see how the Law leads to the Gospel and how Moses testifies to Christ (cf. John 5:39, 46).
In this way, the third use of the law is a vital part of the Christians discipleship. And more, that discipleship depends largely on reading the Law lawfully (1 Timothy 1:8). Practically, this means we walk in the Spirit and obey God’s Law by the power he supplies.
With joy in the good news of Christ, we obey God’s word through faith, prayer, and humble dependence on God. In truth, this way of walking is not without difficulty or setbacks, but for those who have been led by the Spirit to Christ (i.e., the second use of the Law), they are now empowered to to experience the fruit of the Spirit—realities of love and joy that are sown and grown by ongoing meditation on God’s Law.
Read the Law Lawfully
All in all, we need the manifold ministry of the Law and can give thanks to God for all the ways it works in our lives. Moses, and the Prophets who came behind him, are not voices opposed to the gospel. They are instead prophetic witnesses to God’s holiness and the Christ to whom the Spirit led them to proclaim (Romans 3:21; 1 Peter 1:10–12).
In these ways, we should read the Law in all of its fullness. In its historical context (the first use), we learn how it instructed its original recipients; in its covenantal context (the second use), we see how it fits in redemptive history and prepares us for the gospel; and in its canonical context (the third use), we see how it gives Spirit-born believers wise instructions for life in covenant with God. Altogether, these three uses of the Law give us (with the New Testament) all we need for life and godliness.
For that reason, let us give ourselves to the Law and the gospel it foretells. From the Apostles, let us learn how to read the Law lawfully which bolsters our faith in Christ.
Soli Deo Gloria, ds
 Louis Berkhof, Systematic Theology (Grand Rapids: Eerdmans, 1938), 614–615. I have removed/translated the Latin to render the passage more clear.