In the previous article, we examined The Error of Legalism. In discussing legalism, one issue that always emerges is the place of the Law (Moral Law) in Christian living. If a Christian is saved by grace through faith and not by works (Eph. 2:8-9), then what is the place of the law or works in the life of the believer? If we are not under the law, can a Christian therefore live their life carelessly? These questions present us with another error, the opposite of legalism—antinomianism.
The word antinomianism comes from the Greek anti, against, and nomos, law. It is the unbiblical practice of living without regard to the righteousness of God, using God’s grace as a license to sin, and trusting grace to cleanse of sin. In other words, since grace is infinite and we are saved by grace, then we can sin all we want and still be saved. 
While legalism says “Law”, Antinomianism says “No Law.” In the creed of the antinomian, it is all grace and no obedience. Paul addressed this in Romans 6:1 after he had extensively spoken about the free gift of God’s grace through faith. In Romans 5:20, he made a startling statement: “where sin increased, grace abounded all the more.”(Rom. 5:20). This, if superficially read will appear as a license to sin. Perhaps by the inspiration of the Holy Spirit, Paul envisaged that and quickly retorted: “What shall we say then? Are we to continue in sin that grace may abound? By no means! How can we who died to sin still live in it? (Romans 6:1-2). The King James presents us a weightier rendition of Paul’s own answer to his question: “God Forbid”. Yes, God forbid that those of us who have come to faith in Christ will live contrary to what we profess (1 Peter 1:14-19).
The grace of God calls us to a higher responsible living.
For the grace of God has appeared, bringing salvation for all people, training us to renounce ungodliness and worldly passions, and to live self-controlled, upright, and godly lives in the present age, waiting for our blessed hope, the appearing of the glory of our great God and Savior Jesus Christ, who gave himself for us to redeem us from all lawlessness and to purify for himself a people for his own possession who are zealous for good works (Titus 2:11-14).
Notice the last line of the text above: “a people… who are zealous for good works.” The believer is saved for good works which includes obedience to the commands of God. As Paul said in Ephesians 2:10 we are created for good works. The question I will attempt to answer is “What is the place of the law in a believer’s life?” I will turn again to the definition of legalism as supplied in the previous article and from there, examine the place of the law in a believer’s life.
Legalism is the excessive and improper use of the law (10 commandments, holiness laws, etc.). This can take different forms. The first is where a person attempts to keep the Law in order to attain salvation. The second is where a person keeps the law in order to maintain their salvation. The third is when a Christian judges other Christians for not keeping certain codes of conduct that he thinks should be observed. 
Notice the first line of the definition: “Legalism is the excessive and improper use of the law.” This tells us there is a proper use of the law. Among those of the Reformed Faith or Reformed Tradition, there is what is held as The Threefold Use Of The Law. This threefold use of the law is captured differently by various authors of the tradition yet they all converge on a threefold use. In this article, I will examine The Threefold Uses of the Law from John Calvin’s Institutes of The Christian Religion.
The Law Is A Mirror
This is the first use of the law. As a mirror, it reflects to us the righteousness and holiness of God and then shows us our own sinfulness. This use of the law reveals to us our wretchedness and need of a Saviour. Indeed, of ourselves, we are unable to meet up the standard of God’s holiness despite the fact that the law demands precisely that: “You shall be holy, for I am holy.” (Lev. 11:44; 1 Pet. 1:16). So God’s law strikes us with our deadness and we seek out desperately where to find solace for our soul. The law, unfortunately is not able to give us that solace and to grace we must turn.
The Law is a kind of mirror. As in a mirror we discover any stains upon our face, so in the Law we behold, first, our impotence; then in consequence of it, our iniquity; and, finally, the curse, as the consequence of both. He who has no power of following righteousness is necessarily plunged in the mire of iniquity, and this iniquity is immediately followed by the curse.(Institutes of The Christian Religion 2.7.7) 
Calvin further quotes Augustine to buttress his point: “The Law orders, that we, after attempting to do what is ordered and so feeling our weakness under the law, may learn to implore the help of grace”
The Law Restrains Sin
Left on our own without the restraining power of God through his law we would, without hesitation live out our full evil inclinations. But the law of God restrains us. It checks us. We don’t live out our evil desires because we have in us a conscience which guides and restrains us from all evil possible under the sun.
The second office of the Law is, by means of its fearful denunciations and the consequence dread of punishment, to curb those who, unless forced, have no regard for rectitude and justice. Such persons are curbed not because their mind is inwardly moved and affected, but because, as if a bridle were laid upon them, they refrain their hands from external acts, and internally check the depravity which would otherwise petulantly burst forth. (Institutes of The Christian Religion 2.7.10) 
The Law Points Us To What Pleases God
But for the law, none of us would have the slightest idea of what pleases God. It is the law that tells us “Don’t murder” and hence we know murder displeases God. It is the law that tells us “Don’t commit adultery”. It is the law that tells us not to have any god apart from God. So in the law, we get to know what God demands of us. And for the believer, this is the most crucial use of the law. We turn to the law to know what God demands, then we turn to Christ for the grace to obey God’s demands.
Even in the case of a spiritual man, inasmuch as he is still burdened with the weight of the flesh, the Law is a constant stimulus, pricking him forward when he would indulge in sloth. David had this use in view when he pronounced this high eulogium on the law: “The law of the Lord is perfect, converting the soul: the testimony of the Lord is sure, making wise the simple. The statues of the Lord are right, rejoicing the heart: the commandment of the Lord is pure, enlightening the eyes(Ps.19:7,8)” (Institutes of The Christian Religion 2.7.12) 
Dear believer, grace doesn’t obliterate obedience to the commandments of God. Indeed the evidence of our love for God is our obedience to his commands: “If you love me, you will keep my commandments.” (John 14:15). Don’t fall prey to any system of belief that demolishes obedience in the Christian walk.
1 Matt Slick, “Antinomianism”, https://carm.org/dictionary-antinomianism, accessed 14th April 2019
2. Matt Slick, “What Is Legalism”, https://carm.org/what-is-legalism, accessed 7th April, 2019
3. John Calvin, Institutes of The Christian Religion, trans. Henry Beveridge (Peabody: Massachusetts, Hendrickson Publishers Marketing, 2008), 222
4. John Calvin, Institutes of The Christian Religion, 222
5. John Calvin, Institutes of The Christian Religion, 224
6. John Calvin, Institutes of The Christian Religion, 225