If Christians are confused about the Gospel, they are flummoxed about the law. Many of them know a few biblical texts that have become dismissive catchphrases: “You’re not under the law, but under grace” (Rom. 6:14). “We’re free from the law” (Rom. 8:2). “The letter kills, but the Spirit gives life” (2 Cor. 3:6). “Christ is the end of the law” (Rom. 10:4). Armed with these and a few other texts, they see the law as at best obsolete and at worst, harmful. Jesus came to get rid of the law (Jn. 1:17), and that is that. The NT writers (they think) have given us some instructions for life, but it has nothing to do with the law.
This dismissal is woefully one-sided and in fact, flat-out wrong. This post won’t permit anything resembling a complete discussion of the Christian law, but let me make a few points to exhibit in summary form simply the blessing of the law as the Bible depicts it.
Holy, Righteous, Good
First, the law is holy, righteous, and good (Rom. 7:12). How could it be anything else? The law is a reflection of God’s character. We read in Leviticus 20:7–8,
Consecrate yourselves, therefore, and be holy, for I am the Lord your God. Keep my statutes and do them; I am the Lord who sanctifies you.
“Be ye holy, for I am holy.” We must be holy like God is, and to be holy is to obey God’s law, for God’s law exhibits his character. To know the law of God is to know the character of God, in other words, to know the law is to know God. Some Christians might chafe at this description. Isn’t the law opposed to the grace of God, for example? And don’t we need to know the grace of God in opposition to the law of God? We do not. If the law of God is a reflection of his character, the law reflects his grace. This is why in Exodus 19:4–5, before he gave Israel the Mosaic law, God points out how gracious he is to his people in giving that law. The law exhibits God’s grace.
Moreover, when Jesus died on the cross, God was fulfilling the terms of his law. The cross demonstrates the love of God because it demonstrates the law of God (Gal. 4:4–6; Rom. 5:6–11). God loved us so much that he gave up his own Son to the law’s justice. Remember that the only law to which God’s grace is antithetical is a manufactured, homemade law apart from Jesus Christ. But that’s not the proper use of the law. If you want to know what God is like, read the law. If you know want to know what God is like, look to Jesus Christ (Jn. 14:9), whose life and death fulfilled the law (Gal. 4:4).
Second, the law promises life (Rom. 7:10). This statement might perplex us, since Paul writes that the law doesn’t bestow life (Gal. 3:21). Only the Messiah can bestow life. However, the law does promise life to those that live within it (Dt. 30:1–16; cf. Rom. 10:5 –13), because if we live within it, we won’t rely on ourselves for salvation, but on Jesus Christ. This is another clue that many of Paul’s opponents weren’t following the OT law but a twisted, Christ-less, grace-less, faithless version of it. Not only will we know God if we live within the law. We’ll also be led into life. To live in this sphere of the law is to gain life. The law doesn’t bestow life, but the law points us to the One who does, Jesus Christ, and in him alone we should trust.
In addition, when we’re united to Jesus Christ, the Holy Spirit leads us to obedience that elicits God’s blessings. If we obey, God blesses us. If we disobey, God judges us (Gal. 6:7–8). If we completely and finally turn our backs on God, he expels us from his kingdom (2 Pet. 2:17–22). What are we to obey? We are to obey God’s law. This is why the law promises life. To live within the law is to live within absolute trust in Jesus Christ and in obedience to him.
Third, the law bestows liberty (Jas. 1:25, 2:12). This is counterintuitive to many Christians today. For them the law is heavy and burdensome. They might get this idea from Acts 15, which tells of the Jerusalem council, where Peter identified the law as a heavy yoke (v. 10). But it seems they might have missed v. 1. The great error being combated at the council is the teaching that one must keep the law as a way of salvation. Of course, this is precisely what the law was never intended to do. When the law is turned into a system of works-righteousness, it does indeed become a yoke and a burden. This is a pharisaic and Judaic perversion of the law.
The yoke the Lord Jesus imposes is easy and his burden is light (Mt. 11:29–30). Why is this? Because God is our Creator, he knows precisely how we are to operate within his world. His law, his instruction, is suited to man as the earth-bound creature made in his image. We might say that the law is the instruction manual for humanity. And this isn’t limited to the Mosaic law, but includes God’s entire word, which instructs us (1 Tim. 3:16–17). It is in the sense that we could say that the entire Bible is law. It’s God’s revelation for how we should believe and live. God knows how we should live much better than we do. That’s why he gave us his word, his law. To turn away from God’s law is to turn away from the only truth that will help us to live with great blessing and profit in God’s world. We live in a God-rigged universe. Far from being hard and onerous, God’s law shows us how to live within our environment with the greatest of light and blessings.
Fulfilled in Believers
Fourth, the law is fulfilled in us (Rom. 8:4). If we ask the question, Can anybody fulfill or obey the law, the answer is, No and Yes. No, everyone has sinned and fallen short of God’s glory (Rom. 3:23), and if we break one commandment we have violated all (Jas. 2:20). However, believers, by the power of the Spirit, can fulfill the law as much as a redeemed sinner can. This is why 1 John tells us that everyone sins (1:8), but also that we must not live within the reign of sin (2:4–6), which is a violation of God’s law (3:410). In other words, to live by the Spirit’s power is to live in obedience to the law. In this sense, we can keep the law. No, not flawlessly, but nonetheless faithfully (see Gen. 26:5; 1 Kin. 11:24; Lk. 1:6; Jn. 15:10). In a post-Fall world, the issue is not whether a person can be flawlessly sinful. It’s whether a person can live a life dominated by righteousness. He certainly can — and must. “In the natural man sin is the essential element, but in the new man sin is an alien element.”  Therefore, the most faithful Christians are those who’ve most faithfully kept God’s law. The best Christians are the best law-keepers.
In Harmony with the Gospel
Finally, the law is not contrary to the Gospel promises (Gal. 3:21). Paul makes this point quite emphatically (see vv. 21–29), and if we understand it, we might never again have a problem reconciling the law and gospel, law and grace, law and promise. The Mosaic law was given to Israel subsequent to the Abrahamic promises. The promises are promises of eternal life. The law was never given to impart eternal life. It has given, as we have seen, to lead us toward eternal life, that is, toward the Gospel promises (see v. 24). The law is not against the promises, precisely because they serve different functions. The promises tell us what God has accomplished, is accomplishing, and will accomplish in Jesus Christ. The law tells us how we are to live in relation to Jesus Christ. We are not saved by keeping the law, and no one was ever saved by keeping the law in any era. In addition, no one was ever led to please God without the law. Hebrews 11 tells us that without faith it is impossible to please God (11:6), and then it moves on to tell us how that faith led the great OT saints to great exploits of obedience, in other words, law-keeping. To perceive the law as a means of salvation or justification is to pervert it. To see it as a means of pleasing God is to see it precisely as God intends.
How to explain the verses that speak disparagingly of the law is a topic for another post, but suffice it to say that swiftly dispensing with God’s law is a contra-biblical move.