Galatians 3:6-9 meaning

Here, Paul quotes Genesis 15:6, "Abraham believed God and it was reckoned to him as righteousness." This is a verse Paul also cites in the letter to the church in Rome when he addresses a similar type of confusion about law and faith.

It was Abraham's faith that gave him a right standing with God, specifically his faith in God's promise. God promised Abraham that the number of his offspring would be larger than the number of stars in the sky, and Abraham believed Him. Here, Paul argues that it is not simply the Jewish people who are the offspring of Abraham, but those who are of faith (e.g. believe in the promise of God in Christ). And God promised Abraham that all nations will be blessed in you, not just the Jewish people. And those who are of faith are blessed with Abraham, the believer. Jesus the son of David, Abraham's offspring, has provided a means for Gentiles to join Abraham's family through faith. Just as Abraham is a believer, the Gentiles are believers, and are justified in the sight of God through Christ.

The message of Galatians is clear: Paul is showing the audience that it is through faith that Abraham and everyone else gains right standing with God, not following religious rules (works of the law).