Verse 23

The law's purpose illustrated (3:23-4:7)

Jews under the law were like children under the control of a guardian, but this was only in anticipation of the coming of Christ. When he came, those who trusted in him were forgiven the sins they had committed against the law and were put right with God. Instead of being like children under a guardian, they now enjoyed the freedom of full-grown mature sons of God (23-26). Since the coming of Christ, all believers are united in him and are God's children, regardless of race, social status, sex or the law. Being part of Christ, they are part of Abraham's promised offspring. Those justified by faith are Abraham's true descendants (27-29).

Paul gives another example, similar to the first, to illustrate the law's function. A child who inherits his father's property cannot do as he likes with it until he has reached the age of an adult. Though legally the owner, in reality he is little different from a slave, being under the control of guardians who manage his affairs for him (4:1-2). This illustrates the position of those previously under the law. They were like children receiving instruction. But Christ came and fulfilled the law's requirements, so that those under its control could be released to enjoy their inheritance as adult sons of God (3-7).

Verses 8-20

Paul's concern for the Galatians (4:8-20)

Before they believed in Christ, most of the Galatians were pagans, in bondage to idols of wood and stone. Now that they have come to know the true God, they are foolish to get into bondage again by trying to keep the Jewish law. By doing so they are not going forward in their Christian lives; they are going backwards (8-11).

The Galatians should live as those free from the law, just as Paul does. He feels sorry for them, not angry with them. He does not consider their error to be an attack on him personally, and he still has the most pleasant memories of their kindness to him when he was ill while visiting them (12-14). They would have done anything for him then, and he hopes they will not turn against him now because of his attempts to correct their error (15-16).

Part of the Judaisers' tactics in trying to gain control over the Galatians was to turn them against Paul personally. Paul is certainly not jealous when others show interest in his converts after he has gone, provided they have pure motives (17-18). He is concerned only for the Galatians' good and he is prepared to put up with any suffering to help their Christian lives grow and develop. If it were possible he would visit them rather than write, for he is worried about them (19-20).

Verses 21-31

Example of Hagar and Sarah (4:21-31)

Paul now attacks the Judaisers by using a form of argument that they themselves liked to use. He returns to the story of Abraham to show that law-keeping is slavery and it cannot be mixed with grace. (For the background to the illustration that follows read Genesis 15:1-6; Genesis 16:1-16; Genesis 17:15-22; Genesis 18:1-15; Genesis 21:1-21.) Abraham had two sons, Ishmael, who was born as a result of human arrangements that lacked any exercise of faith, and Isaac, who was born in fulfilment of God's promise. The mother of Ishmael was the slave woman Hagar; the mother of Isaac was Abraham's true wife Sarah (21-23).

Hagar is likened to the covenant of law given by God to Israel at Mt Sinai; Sarah is likened to the covenant of grace given freely to all people from heaven. The spiritual descendants of the slave woman are the Jerusalem Judaisers of Paul's day; the spiritual descendants of the free woman are those saved by God's grace through faith (24-26). The Jews, children of Abraham by natural descent, have largely failed to be God's people; the Gentiles, who previously had neither life nor hope but who now largely make up the church, become Abraham's spiritual children. Thus, in Paul's illustration, the slave woman finishes with few offspring, but the free woman, who was formerly childless, now has a multitude of descendants (27).

Ishmael is likened to the Jews who are slaves under the bondage of the law; Isaac is likened to those saved by God's grace and freed from the law. Just as Ishmael persecuted Isaac, so the Jews under the law now persecute those who are God's people through his grace. Children of the law and children of grace cannot live together; the former must be thrown out. There is no place for law-keeping in God's family (28-31).