Why was the book of Galatians written?
Galatians was written to the churches of Galatia to prove to Gentile believers that they were not under law but under grace, because Judaizers were trying to put them under law. The letter uses Hagar and Ishmael versus Isaac to show law and legalism must be cast out, while grace and freedom remain.
Les explains that this little letter was written specifically to the churches of Galatia because the Judaizers were trying to put them under the law. The purpose was to prove to these Gentile believers that they were not under law but under grace. In chapter 4, he points to the analogy of Isaac and Ishmael: Ishmael was of the flesh and earthly, not of the spiritual seed or the promises as Isaac was. Hagar and Ishmael stood for the law and the flesh, and Scripture says, “Cast out the bondwoman and her son.” The son of the bondwoman shall not be heir with the son of the free woman. Ishmael and Isaac could have no interrelationship, because Ishmael stood for law and legalism, while Isaac stood for grace and freedom.