In Galatians 3:19-25 Paul anticipates and answers the question Galatian Jews might have when considering his argument thus far. Namely: what purpose did the Law serve (cf. Galatians 3:19)? Obviously, it had some godly purpose, because for over a millennium the Jewish nation related to God through the Law of Moses. The esteem in which Moses is held among the Jews is probably second only to their honor for Abraham. Moreover, the New Testament concludes that the Law was holy, just and good (Romans 7:12), and that, if life and righteousness have could come through a written code, surely righteousness would have come through the Law of Moses (Galatians 3:21).
At the end of the day, however, it must be said that the Law of Moses was never given to save anyone from sin. This was not its holy purpose. According to God’s word the Law had at least three purposes. First, it was added to punish evildoers (Galatians 3:19); secondly it was added to show us what sin is (Romans 3:20; 7:7); finally it was added to teach us about the nature of evil and help us see the need of deliverance (Galatians 3:24; cf. Romans 5:20; 7:8-9, 13).
Moreover, the Law was a temporary arrangement. Paul points out that the Seed, Christ, would come to replace the Law—“…until the Seed should come” (Galatians 3:19). The Mosaic Covenant was ordained through the mediation of an angel or messenger, namely Moses. The use of a mediator implies two parties and an interdependent or bilateral covenant—a conditional covenant, one dependent upon the faithfulness of both parties. The Abrahamic Covenant, on the other hand was ordained unilaterally by God, himself, so it was dependent solely upon God (Galatians 3:20). It was an unconditional covenant, as far as man was concerned. Likewise, the New Covenant is unilateral. It was ordained by and solely dependent upon Jesus.
Paul concludes by saying that the Law and the promises are not contradictory, because each was ordained for different reasons (cf. Galatians 3:21). The Law was never intended to provide life or justification. It was ordained to punish evildoers and define the nature and the gravity of sin. The promises, on the other hand, are received through faith in Jesus as our Lord (Galatians 3:22). The promises cannot come through a covenant of Law, simply because we are unable to keep such a covenant. We are weak and, by nature, the servants of sin (Romans 7:14).
The Scripture, itself, concludes that we are all under sin (Galatians 3:22), telling us that everyone is a slave of sin, both Jew and gentile alike (Romans 3:9, 19; 11:32). Some people may try to deny they are a slave to sin, but all they have to do in order to prove their point is to stop sinning—completely, not even one infraction. The conclusion is, according to God’s word, we are all sinners. Before the coming of Christ we were kept by God under the Law (Galatians 3:23), meaning that God had shut everyone up in prison under unbelief (Romans 11:32). Both Jews and gentiles are guilty. We have all broken God’s law – the Jews broke the written law, the gentiles broke the law written in their hearts (Romans 1:19-20; 2:14-15). We have all been tried at God’s judgment seat and found guilty and condemned to death. This is our present status and our just wage (Romans 6:29). We are, therefore, held in custody until either our execution is announced or until the time of the fulfillment of the promise to Abraham at the coming of Christ when faith would be unveiled through the Gospel.
The whole world is kept in this hold or prison out of which there is no escape—all are guilty, helpless and in a miserable condition. Through the Gospel God has issued a general pardon (John 3:16), and it is proclaimed to all. Anyone, Jew or gentile, who refuses the conditions of the pardon (faith in the atoning work of Jesus), will remain in the hold or prison. Only those who place their trust in Jesus are set free to obey Jesus as our Lord.
Showing us that the Law was a temporary covenant (Galatians 3:24), Paul personifies the Law by saying it is a tutor. In the first century AD, it was common for children from age 6 to puberty to be placed under a tutor or a pedagogue. The predominant image of a pedagogue was that of a harsh disciplinarian. When the child became an adult, he was set free from the pedagogue. He was no longer under his authority. Similarly, the Law was also temporary until the coming of Jesus and the promises that come to us through him by faith (Galatians 3:25).
The Law cannot justify us; it can only show we are sinners. It cannot sanctify us; it can only enforce its works upon us as a disciplinarian. It can never give us eternal life; it is able only to take that life away from us through judgment.