Galatians 2:16-3:25 contains some of Paul’s most pointed statements about the futility of salvation by works of the law. Any system of law, argues Paul, has only the power to condemn, never the grace to forgive. Thus, the gospel has revealed God’s grace in Jesus Christ that a person might now be saved by faith in Christ, not by works of law. Taken at face value these word are not only welcome relief but a temptation to disparage rules and regulations as a means of approach to God. Yet, we know that God expects his people to exercise holiness and sanctification. So what should a Christian’s attitude be toward the demands of God’s law?
I found this quotation from the New American Commentary on the New Testament very helpful in addressing this issue. In this somewhat lengthy quote is housed a useful way to categorize and understand the Christian’s attitude toward the law of God.
If taken in isolation from the rest of Paul's writings, Gal 3:10-25 can be, and sometimes has been, read as a manifesto of antinomianism. If the law cannot save but only condemn, if it cannot remove transgressions but actually increases them, if we are no longer under its harsh discipline, if Christ is the end (telos) of the law for all who believe, then does the law have any continuing normative significance for the Christian? While we will return to this question in Galatians 5 and 6, we may at this point introduce two important distinctions concerning New Testament teaching on the law.
As we have seen, the Reformers distinguished between the civil or political use of the law, according to which criminals are restrained and human society kept from complete chaos, and the theological or spiritual use of the law, according to which sinners incurred the full penalty of God's righteous judgment and became liable to his curse because of their transgressions. Clearly it is this second, theological use of the law that Paul had been developing in Galatians 3. However, Calvin and Reformed theologians especially also spoke of a third use of the law (tertius usus legis) by which they referred to the abiding significance of the law as a standard of moral uprightness and as a source of spiritual counsel and instruction precisely for those who have been freed from the “bondage” of the law.
However, if one accepts the validity of the third use of the law, it becomes immediately necessary to distinguish further various dimensions or layers of the law as found in the Old Testament. The most commonly accepted schema finds within the law a threefold distinction: the ceremonial law, which included the sacrificial cultus and other regulations such as circumcision that related to the ethnic particularism of the Jewish people; the civil law, which contained the code of behavior and penal sanctions given to Israel as a national entity; and the moral law, the eternal standard of God's righteous rule embodied succinctly in the Ten Commandments. When we speak of the third use of the law, that is of the continuing validity of the law as a moral guide in the life of the believer, we are speaking of the moral law of God and not the law in its civil or ceremonial aspects. Both of these construals, the threefold use of the law and the threefold differentiation within the law, are patterns of interpretation derived from the history of exegesis. While they do reflect an accurate distillation of the overall teaching of the Scripture, they must be used with great caution when applied to a particular text (New American Commentary on the New Testament, Vol. 18, Galatians).