Paul calls the Galatians foolish and asks who has bewitched them, they before whose eyes Jesus Christ was publicly portrayed as crucified. He appeals to their experience: did they receive the Spirit by works of the law or by hearing with faith? Having begun by the Spirit, are they now to be perfected by the flesh?
Then he turns to Abraham, who believed God and it was counted to him as righteousness. So those who are of faith are sons of Abraham, and Scripture, foreseeing that God would justify the Gentiles by faith, announced beforehand that in Abraham all nations would be blessed. Those who rely on works of the law, however, are under a curse, since no one keeps it fully. The righteous shall live by faith. Christ redeemed us from the curse of the law by becoming a curse for us, so that the blessing of Abraham might come to the Gentiles and we might receive the promised Spirit through faith.
Paul illustrates: a covenant already ratified is not annulled and nothing is added to it. The promise was made to Abraham and to his offspring, who is Christ, and the law, which came 430 years later, cannot cancel it. What, then, is the law for? It was added because of transgressions until the offspring should come; it is not against God's promises, but it could not give life. Scripture imprisoned everything under sin so that the promise might be given by faith to those who believe.
Before faith came, we were held under the law as under a guardian who led us to Christ so that we might be justified by faith. Now that faith has come, we are no longer under that guardian. All are children of God through faith in Christ Jesus, and all who were baptized into Christ have put on Christ. There is no longer Jew or Greek, slave or free, male and female, for all are one in Christ; and if they belong to Christ, they are Abraham's offspring and heirs according to the promise.