In a sermon entitled, "Law and Grace," (no. 37) Charles Spurgeon once said, "There is no point upon which men make greater mistakes than upon the relation which exists between the law and the gospel." A distorted understanding of this relation generally leads people into one of two errors: legalism or antinomianism.
Paul clearly and effectively refuted legalism--the belief that one has to keep the law and perform certain ceremonies in order to be saved--in his letter to the Galatians. He pronounced a strong condemnation (let him be anathema--accursed) on anyone who would teach legalism, because it was a false gospel, and would lead people straight to damnation. Paul emphasized God's grace and sovereignty in man's salvation, and made clear that "by the works of the law shall no flesh be justified" for "the just shall live by faith" (3:11). In chapter three, he shows that God's covenant with Abraham included justification by faith (verses 8 and 9), that the law can neither give life nor righteousness (verse 21), and that the law was given to show us our sinfulness so we would know that we needed Christ (verse 24).
If legalism is one extreme, antinomianism is at the other end of the spectrum. Antinomianism (literally, "against law") asserts that obedience to God's commands are not necessary. Antinomians believe that Christ can be someone's Savior, but not necessarily his Lord. This is also a false teaching. Though we can't keep the law to be saved, God gives the Holy Spirit to justified persons as an earnest (down payment) of their ultimate redemption and to enable them to keep His commandments. Obeying God is an evidence that we know Him and love Him (John 14:21, 15:10-17; I John 2:3-5, 3:24, 5:2-3). Professing Christians who are regularly disobedient to God show that they were never truly regenerate. Paul tells Christians to "yield your members servants to righteousness unto holiness" (Romans 6:19).
If we keep in mind the twofold purpose of the law, we shall avoid the errors of legalism and antinomianism. First of all, the law reveals God's holy character. Secondly, the law shines light upon man's helpless, sinful condition. In other words, the law sets forth God's requirements and man's shortcomings.
By showing God's requirements, His holiness is emphasized. The Scripture clearly declares that "without holiness no man shall see the LORD." "God is separate from sinners." His thoughts are higher than our thoughts, and His ways are higher than our ways (Isaiah 55:8-9). Christ Himself came not to do away with the law, but to fulfil it (Matthew 5:17). The law is good, and necessary (Romans 3:31). But its standards are too lofty for sinful man to reach.
The law reveals how exceedingly sinful man is. It illuminates us as to our lost and hopeless condition. When God's law convicts men of sin, it drives them to the point of despair, and even stirs up a greater desire to sin (because of their rebellious nature--see Romans 7). It shows them that no good thing dwells in their flesh, and that they need a Savior. This is how the law is our schoolmaster to bring us to Christ (Galatians 3:24). It teaches us the hard lesson that we need Him. Man does not realize that he needs a Savior until he finally comes to grips with the fact that he is unable to save himself. God was gracious to give the law to man. It is much better to be informed of a bad situation than to be ignorant of it. God is gracious to show man how sinful he is. Well may we sing with John Newton "'twas grace that taught my heart to fear"; but because God saves sinners through faith in Christ, Christians can also sing "and grace my fears relieved."
The bad news is that we can't keep God's law. If we could have, Christ would not have had to suffer for sin (Galatians 2:21). The good news is that Christ has been made the righteousness of God for sinners. Because of the substitutionary atonement of Jesus Christ, men can stand righteous before God. God became flesh to satisfy the demands of His holy justice for the transgressions of sinners; to purchase salvation for His chosen people. Christ put away the sin of those who believe, and gives a robe of righteousness to those He calls. The finished work of Christ is the basis on which we can stand holy and blameless before God. Truly, "where sin abounded, grace did much more abound" (Romans 5:20).
Christ kept the law for His people. Though we are no longer bound to its ceremonial prescriptions, we are bound to obey the moral law. The Lord Jesus summed up the law with two commandments (Matthew 22:37-40, Mark 12:28-31)--love the one true God with all your being, and love your neighbor as yourself. "On these two commandments hang all the law and prophets" (Matthew 22:39). Paul wrote to the Galatians, "Stand fast therefore in the liberty wherewith Christ hath made us free, and be not entangled again with the yoke of bondage…only use not liberty for an occasion to the flesh, but by love serve one another. For all the law is fulfilled in one word, even in this: Thou shalt love thy neighbor as thyself" (Galatians 5:1, 13-14).