In Galatians 4:21-31, Paul gave an interpretation of the story from the Old Testament about Abraham and the two sons he had, one to Hagar the slave woman, and the other to Sarah his wife. The false teachers in Galatia were perhaps using this story to try to force non-Jewish believers to become Jews. However, Paul showed how the story itself supports his main thesis that both Jews and non-Jews may receive God’s promised blessing through faith, not through law-keeping.
God gave us The Ten Words, which show us how to live well and our need for Jesus Christ.
While the Old Testament is still valid, we also have the message of the one who was raised from the dead.
Paul continued to praise God for the benefits believers receive because of the sacrifice of the Son.