Paul wrote Galatians to fortify believers he met during his first missionary journey (Acts 13:1-14:28). He first described the unchanging nature of the gospel (Gal 1:1-11) and then shared his testimony and ministry to date (Gal 1:12-2:14). Paul’s thesis in Galatians was that since Gentiles are justified by faith in Christ, they must not submit to the law as a rubric for Christian living (Gal 2:15-21). In Galatians 3-4, Paul contrasted the old covenant and the new. Paul paired texts from Genesis, Leviticus, Deuteronomy, Isaiah, and Habakkuk to root in the storyline of Scripture his argument concerning justification by faith.
(1) In Gal 3:6 and 8, Paul quoted God’s covenant statements to Abraham in order to establish that justification before God has always been on the basis of faith and not the law. In Gen 15:6 it is written, “Abram believed the LORD, and He credited it to him as righteousness.” Abraham believed God’s promise, the promise God made to him while he was yet in Haran. God told Abraham that He would bless him in both land and lineage such that all nations would be blessed in him (Gen 12:1-3). Paul exhorted the Galatians to be confident in their faith, reminding them that by faith they received the Spirit (Gal 3:1-5) and by faith Abraham was justified (Gal 3:6-9). If they submitted to the law, they would contradict both the Spirit’s work among them and the historical precedent established in Abraham who believed.
(2) In Gal 3:10 and 13 Paul explained his thesis of Gentile freedom by quoting Moses’ curses upon unfaithfulness in Israel. In Deuteronomy 27 and 28 Moses listed the covenant curses and blessings the Lord would exhibit toward Israel based upon their faithfulness, or lack thereof, in the land. Paul quoted Deut 27:26 in Gal 3:10b, writing, “Cursed is everyone who does not continue doing everything written in the book of the law.” Israel did not keep the law—and that was Paul’s motivation for citing the text. Since no one could keep the law, anyone who tried was cursed. But Paul saw in the words of Moses another curse text, citing Deut 21:23 in Gal 3:13: “Cursed is everyone who is hung on a tree.” Moses’ concern was that any who were executed on a tree needed to be removed and buried before nightfall because that person was under God’s curse and the land would be polluted if they hung on the tree beyond the day of their execution. Paul saw Christ as the link between Deut 21:23 and Deut 27:26. The Galatians should stand fast against the threat of those who proposed that Gentiles needed to submit to the law because throughout history all who tried had failed and been cursed—and Christ was cursed for them when He submitted to being crucified.
(3) In Gal 3:11 and 12, Paul explained the means of spiritual life by quoting Hab 2:4 and Lev 18:5. Habakkuk struggled to understand how God could use the ungodly Chaldeans to discipline His people. The Lord told Habakkuk that the Chaldeans would grow so puffed up that He would eventually exhibit His wrath upon them. In the meantime, however, the Lord told Habakkuk and the people of Judah, that the righteous will live by their trust in God to work His plan even if it did not make sense to them (Hab 2:4). Faith was necessary for Habakkuk and Judah if they were going to trust God in the midst of their confusion. Paul said that faith in Christ, not observance of the law, was necessary for spiritual life in Christ. Paul used Lev 18:5, “Keep My statues and ordinances; a person will live if he does them. I am the LORD,” to contrast justification by faith and justification by the law. In Lev 18:1-5, Moses emphasized that as Israel practiced the law and abstained from idolatry, they would enjoy life in Canaan. Paul argued that faith and not practicing the Mosaic law was the basis of life in Christ.
(4) In Gal 4:27 and 30, Paul quoted Isa 54:1 and Gen 21:10 to explain the favored status of those in the new covenant. Paul understood the new covenant to be based upon the supernatural work of God. Because God had empowered Abraham and Sarah to conceive Isaac in their old age, Isaac was a symbol of God’s faithfulness to His promises—unlike Ishmael who was the product of natural conception between Abraham and Hagar, Sarah’s handmaid (Gen 16:1-4; 21:1-7). Paul used Hagar and Sarah to represent the old and new covenants. He saw in Isa 54:1 a prophetic description of God’s faithfulness to Sarah: she was once barren but became the mother of many children. In Gal 4:27 Paul wrote, “Rejoice, O barren woman who does not give birth. Break forth and shout, you who are not in labor, for the children of the desolate are many, more numerous than those of the woman who has a husband.” Paul contrasted the exalted, lofty status enjoyed by those who had received God’s favor in the new covenant with the stern word spoken by Sarah in Gen 21:10, “Throw out the slave and her son, for the son of the slave will never inherit with the son of the free woman” (Gal 4:30). For Paul, there was a chasm fixed between those adhering to the old covenant and those in the new. The participants in the new covenant needed to reject those advocating that the law was the basis of life for Gentiles.