Must the Christian keep the Law of God?

Jeremiah 31:31-34

“Behold, the days are coming, declares the LORD, when I will make a new covenant with the house of Israel and the house of Judah, not like the covenant that I made with their fathers on the day when I took them by the hand to bring them out of the land of Egypt, my covenant that they broke, though I was their husband, declares the LORD. For this is the covenant that I will make with the house of Israel after those days, declares the LORD: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people. And no longer shall each one teach his neighbor and each his brother, saying, ‘Know the LORD,’ for they shall all know me, from the least of them to the greatest, declares the LORD. For I will forgive their iniquity, and I will remember their sin no more.” (Jeremiah 31:31-34 ESV)

Christians must absolutely keep the law, for they have been brought into a new covenant and the purpose is to take them to heaven where righteousness dwells. The problem with the old covenant was not the covenant itself for how can God give something that has a defect, being infinitely holy? The problem was that being external the Israelites broke it. 

So God here promises to make a covenant characterized with the following:

1)      He will put His law within them – it is His own work done in the believer, by His Spirit in regeneration and the continuing work of sanctification.

2)      He will write His law on their hearts – God will make the covenant efficacious and effective, causing, demanding and guaranteeing obedience.

3)      He will be their God and they shall be His people. This is a gracious relationship that depends on God’s own initiative.

4)      No longer shall each one teach his neighbor teach his brother saying, ‘know the Lord’ for all shall know God – from children to the old – it is in the conscience as Paul writes in Romans 1.

5)      He will forgive their iniquity and remember their sins no more – it is marked by forgiveness of sins, sin is dealt with by God gradually, through sanctification, until there is no more remaining sin at the time of glorification

The terms of the new covenant were still within the requirement of law keeping, for it must always be noted that the law and grace as revealed in Scripture are parts of one harmonious and progressive redemptive plan, conceived by a Holy God, and executed graciously to make us holy – for He chose us before the foundation of the world to make us holy and blameless before Him. The present dispensation is spoken of as the age of grace, not because grace belongs to it exclusively, but because in it grace has been fully manifested. When John declared that ‘…the law was given by Moses, but grace and truth came by Jesus Christ’, (John 1:17) he was contrasting law and grace, not as two contrary and irreconcilable systems, but as two related parts of one system. Therefore, salvation through faith by grace is not opposed to the Christian’s obligation to keep God’s law. So the old and the new covenant differ not in substance but in the different ways of administration. In all the covenants after the Fall, there is the same Christ (looking forward to Him or He has already come), the same faith, the same recovery of sinners by God providing the means of the forgiveness of their sins. We therefore have to understand Hebrews 8:8,10 quoted from Jeremiah 31 as referring to the same covenant distinguished in the manner of administration.

Secondly, observe from Jeremiah 31 that our new covenant membership actually shows that we ought to keep the law.  Why else would God be interested in putting and writing His law in the hearts of the people in the new covenant? Moreover, why is it necessary to have an arrangement where everyone knows the Lord?

 It has been said that he who understands the two covenants is a theologian. The heart of every real Christian is most reverent towards the law of the Lord. So that like Paul we can say, "The law is holy, and the commandment holy, and righteous, and good." (Romans 7:12) And like Paul and David, a man that God said was after His heart said, —"I delight in the law of God in my inner being” (Rom. 7:22). C.f. Psalm 119:70, 92. You show your justification, which is by faith alone through your sanctification. But a sanctification that stops short of perfect conformity to the law of God cannot truthfully be called perfect sanctification, for any deficiency of exact conformity to the perfect law is sin. For sin is lawlessness. Do you think there is lawlessness among the angels in heaven? No, for then they would have been ejected from the presence of the infinitely holy God to absolute wickedness, perdition and its consequent misery just like the fallen angels. Clearly, when the Lord in the Sermon on the Mount said, 

“For truly, I say to you, until heaven and earth pass away, not an iota, not a dot, will pass from the Law until all is accomplished.” (Matthew 5:18)

He meant that the Law of God is perpetual to all eternity and that it will be accomplished or fulfilled and this, fulfillment certainly does not mean that it will be nullified, or abrogated for believers. There is no abolition of it, nor amendment of it. It is not to be toned down or adjusted to our fallen condition. However, every one of the Lord’s righteous judgments abides forever. The Lord gave three reasons for this –

(1)    Christ Himself came to fulfill it, not to abolish it – this is to say that the gospel that demands faith, is actually seeking to uphold the law. Do we then overthrow the law by this faith? By no means! On the contrary, we uphold the law (Romans 3:31). The gospel is the true means given by God to establish and vindicate the law for Jesus did not change the law, rather He explained it to the ones who were seeking to change it by externally and hypocritically keeping it. He emphasized its spiritual nature, that is, the Holy Spirit applies it in the heart. In this fulfilling the Law of God, the Lord Himself lived a life of perfect obedience. He said, “I have kept my Father’s commandments and abide in his love.” (John 15:10), so that He ‘well pleased’ the Father. Shall we do anything less than our Master and Saviour? It is actually, because of Christ’s high regard for the law that He willingly gave His life to pay the penalty due to all lawbreakers, so that He satisfied the justice and its legal demands. Christ so highly regarded the law that He gave His own life and shed His blood to satisfy its demands for His people! If you keep my commandments, you will abide in my love, just as I have kept my Father's commandments and abide in his love. These things I have spoken to you, that my joy may be in you, and that your joy may be full. (John 15:10-11)

(2)    The nature of the law shows that it is perpetual. Surely right must always be right, truth must always be true, and purity must always be purity – it is ever unchanging in the eyes of the Eternal God who gave it, For Jesus Christ is the same yesterday, today and forever more (Hebrews 13:8). Every good gift and every perfect gift is from above, coming down from the Father of lights with whom there is no variation or shadow due to change (James 1:17). Before the Ten Commandments were published at Sinai there was still that same law of right and wrong laid upon us by the necessity of being God’s creatures. Right was always right before a single command had been committed to words. When Adam was in the garden it was always right that he should love his Maker, and it would always have been wrong that he should have been at cross-purposes with his God. It does not matter what happens in this world, or what changes take place in the universe, it never can be right to lie, or to commit adultery, or murder, or theft, or to worship an idol for God. To imagine that there will be hatred for God and idolatry and adultery in heaven, that there will be murder in glory, is to fail to comprehend the immeasurable holiness, purity and moral excellence of God. Clearly the law demands no more than is good for us and good continues to work out eternal good for His people. It is for both our immediate and eternal good that we do not get ourselves messed up in sin. It is never for a man’s good to do what God forbids him. It is never for man’s real and ultimate happiness to not do anything that God commands him. The wisest directions for spiritual health, and for the prevention of evil, are those directions that are given us concerning right and wrong in the law of God. What this means is that the law is for our good so that there is assurance of our own justification – for it is only a fool who can consider himself justified when living in sins! The law is holy, and the commandment holy, and righteous, and good." (Romans 7:12)

(3)    The law must be perpetual because if it is altered is most dangerous: By lowering the law you weaken its power in the hands of God as a convincer of sin. Most men will take care to adjust it so as to give themselves as much latitude as possible. By removing the law you have done away with sin, for sin is the transgression of the law, and where there is no law there is no transgression. When you have done away with sin you may as well have done away with the Saviour and with salvation, for they are by no means needful. When you have reduced sin to a minimum, what need is there of that great and glorious salvation which Jesus Christ has come to bring into the world? The problem is that people are not consistent in their seemingly logical arguments. If you opted to adjust and change the law of God so that you allow the minimum, then such obedience would only be according to your own standard and not that of God – such is not holiness and without holiness there is no heaven (Hebrews 12:14)