I hope you will take the time to open your Bible and read these verses in their context. Context is everything. It determines both meaning and application. You also might want to review the definitions from my last blog on Galatians.
For if I rebuild what I tore down, I prove myself to be a transgressor. For through the law I died to the law, so that I might live to God. I have been crucified with Christ. It is no longer I who live, but Christ who lives in me. And the life I now live in the flesh I live by faith in the Son of God, who loved me and gave himself for me. I do not nullify the grace of God, for if righteousness were through the law, then Christ died for no purpose (Galatians 2: 18-21).
Paul was saying that God’s gift of righteousness to us is based entirely on the work of Jesus our Savior—his perfect life, his suffering and death in our place, and his resurrection. The ground we stand on for hope for eternal life is based on Jesus’s blood and righteousness. That is Paul’s whole argument here: nothing we do can be added to what Jesus has done for us. To depart from this is to leave the gospel.
Now the question is: What about the Old Testament? Do we just toss it out? Is it merely biography or a history of the nation of Israel? Paul answers by sharing his own experience. The law has shown him to be a sinner (2:18). It “killed” him–showing him his own unrighteousness and destroying any hope of becoming righteous. When he came to understand the Tenth Commandment, he discovered even his thoughts and desires could be unacceptable. But now he could live with his relationship with God as his life focus instead being burdened down by his efforts (and failures) to keep the law. The law had no more power over him; he had died to the idea that if he kept the law he could live forever. Now he had the Holy Spirit and lived by faith and believed his righteousness did not come from anything he did, but was imputed to him through the grace of God.
Here Paul is using his own experience as his argument against false teaching. In his later letter to the Romans, he develops his thought into more detail (See Romans 1-8). But, you see the simplicity of what he is saying? The Old Testament remained useful to him to show him his sin and his need of a Savior’s death and perfect life. Now he was free to enjoy and pursue his personal relationship with God. Even these Gentile believers were heirs to God’s promises, and everyone was on equal footing—all were Abraham’s children. (See Galatians 3:21-29).
The children don’t toss out their father’s riches; we don’t toss out the Old Testament, but use its promises and examples for our encouragement and its precepts to show us how to live wisely, keeping our focus on our relationship with God. Since our righteousness is a gift from God, we don’t have to improve on it–or add to it by imposing a ritual or a diet or any other rule. The traditional Catholic teaching has been to add things to do so we can be more holy. But, Paul refuted this by making Jesus’s blood and righteousness our only ground of hope for acceptance by God. The Jehovah Witnesses reject the diety of Christ Jesus, and so their ground of hope is shaky. If Jesus is not truly God, then is his sacrifice perfect and sufficient? Don’t we have to do more? Add to it? These are the very teachings that Paul was confronting in Galatians except there it was coming from people of Jewish background.
Those who have faith are free to enjoy a walk with God–to get to know Him. …” if righteousness were through the law, then Christ died for no purpose” (Gal.: 2:21).