Paul’s son/slave analogy (4:1-7) does not illustrate how obedience to God is optional for Christians, as some say. Rather, it illustrates how a Jew’s relationship with the Law of Moses changes when he believes.
Prior to believing in Jesus, a Jew under the old covenant is comparable to a child of a wealthy Roman family in ancient times. He is under “guardians and managers” at first, and his life bears little difference to that of a household slave (4:2). He is, however, destined for better things as he grows older, and at the date set by his father, is adopted into his family to enjoy the full privileges of sonship. Similarly, God the Father set a time when the Jews, in slavery under the Mosaic Law, would be freed through Jesus’ sacrifice to become His full-fledged children, born of His Spirit. Clearly, Paul believed that no Jew (or Gentile) was obligated to obey the Law of Moses.
However, under the influence of the false teachers who had infiltrated the church, not only were Gentile believers being circumcised and embracing the Law of Moses, but Jewish believers were apparently reverting to their former slavery to the Law’s ritualistic aspects (4:9). Notice it was not the Galatians’ holiness or morality that caused Paul such great concern. Rather, he wrote, “You observe days and months and seasons and years. I fear for you…” (Gal. 4:10-11). Paul was concerned that the Galatian Christians were trying to merit salvation by means of circumcision and following ritualistic aspects of the Law of Moses.
Finding himself now in competition with the false teachers for the hearts and minds of the Galatian believers, Paul asks them to remember their special relationship with him. He reminds them that, even though he had “bodily illness” (or better translated, “bodily weakness”) that “was a trial” to them when he was with them, they did not despise him (4:13-14). Paul must have been referring to his appearance after he had been stoned and left for dead in Lystra (Acts 14:19). Imagine how he looked until his swelling subsided and his bruises slowly healed. His appearance, however, only served to endear him even more to the Galatian believers, as they knew he had suffered for their sakes.
Some commentators try to convince us that because Paul told the Galatians, “If possible, you would have plucked out your eyes and given them to me” (4:15), Paul must have had a terrible eye disease! If I say to someone, “You loved me so much you would have cut off your right hand for me,” does that prove my right hand is diseased? Hardly. We would wonder how Paul would have been able to inspire people in Galatia with faith to be healed if he himself had been suffering a terrible eye disease.
Paul’s second analogy in today’s reading, constructed using Old Testament imagery, also serves to help Jewish believers understand their new relationship with God apart from the Mosaic Law.
Abraham’s son Ishmael was born because of Abraham’s own efforts, while his son Isaac was born supernaturally because of his faith. Additionally, Ishmael’s mother was a slave, whereas Isaac’s mother was free. Clearly, Ishmael represents unbelieving Jews who are in slavery to the Mosaic Law as they attempt to obtain salvation by their own efforts, whereas Isaac represents believing Jews who are free from slavery to the Mosaic law, having received salvation through faith.
Paul draws a few additional parallels in his allegory. Hagar the slave, and the Law of Moses, correspond with “the present Jerusalem,” a city in which most of the residents in Paul’s day were still in bondage to the Law. Believers in Christ, however, look to the Jerusalem above, the New Jerusalem, as their true home or “mother.” And just as Isaac was persecuted by Ishmael, so those who are “born of the Spirit” (believing Jews) are persecuted by those who are “born of the flesh” (unbelieving Jews).
What will be the final outcome? The children of the “bondwoman” (those still in slavery under the Law of Moses) will be “cast out,” while the children of the “freewoman” will inherit salvation (see 4:30-31). Interesting shadowy parallels from the Old Testament!