Paul set forth the glorious doctrine of justification by faith in Romans; in Galatians he must meet a challenge to that teaching. Certain Jewish Christian teachers sought to force Gentile converts to keep the law of Moses, and as a token act of submission, to be circumcised. Paul reacted passionately to this amending of the gospel.

His thesis occurs in 1:4 as he writes that Jesus "...gave himself for our sins to rescue us from the present evil age, according to the will of our God and Father, to whom be glory for ever and ever. Amen." Paul states that it was the intention of Jesus to give himself to accomplish our deliverance or rescue from the evil that surrounds us. Either he accomplished this or he did not. If not, both he and the Father who willed this work would be failures. It was the Spirit who applied the gracious work of Christ in our hearts, as Paul discusses later in the letter. The Spirit would be a failure if he needed our help to complete his work, as Paul argues in 3:3.

Adding circumcision as a requirement would essentially alter the gospel until it was no longer the gospel, something, Paul argues, that neither he nor an angel from heaven had the right to do. If circumcision is essential, then it would of necessity be the final step in the accomplishment of one’s salvation, making righteousness attainable only through obedience to God’s law. Righteousness would not be a matter of imputation by faith. Paul strongly asserts that our salvation follows the pattern of Abraham, that we are children of Abraham and heirs of the Abrahamic promise. That promise comes by faith, and as Abraham believed God and God credited it to him as righteousness, so we are imputed with righteousness when we believe.

"If a law had been given that could impart life, " Paul writes, "then righteousness would certainly have come by the law." (Gal. 3:21) Obviously, in such a case, Jesus’ death on the cross would be unnecessary, as Paul states: "I do not set aside the grace of God, for if righteousness could be gained through the law, Christ died for nothing!" (Gal. 2:21) This is a vitally important statement. Christ either did the work for us, or he did not. If his work needs to be supplemented by ours, then it is not complete. If our work is the decisive factor in our salvation, Christ’s death is for nothing.

What then is the purpose of the law? Paul explains as plainly as possible that the law was a pedagogue to bring the child to school. The pedagogue was literally one who leads a child, and was usually a slave who conducted the child to his teacher, encouraging him along the way and reinforcing the lessons of the teacher. The law, by showing us our sin and need for salvation, conducts us to the Master, Jesus Christ, who alone is our savior.

Paul develops the concept very forcefully that we are the children of God; we are not children of slavery, like Ishmael, the son of the slave woman Hagar, who represents the children of the Mosaic covenant. We are children of the free born, children of Abraham, heirs of the promise, adopted children of God by unnatural means, as Isaac who was born of Sarah. As children, who know we are children by the Spirit, we can cry "Abba, Father." As free born children of God, we must develop the Spirit induced fruit that identifies us truly as heirs according to the promise.

This amazing little letter is so valuable because it explicitly sets forth salvation by the promise of the Father, the atoning work of the Son, and the application and guidance of the Spirit. It sounds the death knell to legalism, to the requirement of any human work in salvation, and reveals the true characteristics of the Spirit-created and Spirit-led life in its glorious freedom and godliness.