Paul is making a clear distinction between the law and faith. The law, as given in the Old Testament, is about following specific commandments and regulations. It operates on the principle that if you do these things, you will live by them, meaning that your life and righteousness depend on your ability to keep these laws. However, Paul points out that this is not the way of faith. Faith is about trusting in God's promises and grace, rather than relying on one's own ability to fulfill the law perfectly. This is a central theme in Paul's letters, where he often contrasts the old covenant of the law with the new covenant of grace through faith in Jesus Christ.
By highlighting this difference, Paul is encouraging believers to understand that their relationship with God is not based on their ability to keep the law, but on their faith in Christ. This message is liberating because it shifts the focus from human effort to divine grace. It reassures believers that their righteousness comes from faith in Jesus, who fulfilled the law on their behalf, rather than their own imperfect attempts to adhere to the law. This understanding is foundational for living a life of faith, free from the burdens of legalism.