Galatians 3:1-9 (ESV)
O foolish Galatians! Who has bewitched you? It was before your eyes that Jesus Christ was publicly portrayed as crucified.  Let me ask you only this: Did you receive the Spirit by works of the law or by hearing with faith?  Are you so foolish? Having begun by the Spirit, are you now being perfected by the flesh?  Did you suffer so many things in vain—if indeed it was in vain?  Does he who supplies the Spirit to you and works miracles among you do so by works of the law, or by hearing with faith—  just as Abraham "believed God, and it was counted to him as righteousness"?
 Know then that it is those of faith who are the sons of Abraham.  And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, "In you shall all the nations be blessed."  So then, those who are of faith are blessed along with Abraham, the man of faith.
Faith, the gift of the Holy Spirit comes through hearing, not by works of the law. For instance it is not the result of prayer, which God commands us to do. Yet prayer a work of the law in one sense, is the fruit of faith and the Holy Spirit working in us. One who does not have faith in God, does not pray to God. Paul says “it was before your eyes, that Jesus Christ was portrayed as Crucified.” This is the content of the gospel, Jesus Christ crucified for your sins. It is this gospel that works faith in us. This faith manifests itself in fruit, such as baptism, confession of faith, and other good works. Paul chastises then the Galatians for being bewitched by the law and works of the flesh. If we begin by the Spirit, that is in faith, we cannot then perfect this beginning, end it in the flesh. Our works do not perfect our faith, our faith perfects our works. So we like Abraham believe God that he has forgiven our sins, and it is counted as righteousness. So then we are sons of Abraham, the new Israel. So it is that all nations have been blessed through Abraham, reaping the benefits of His faith, the forgiveness of sins in Jesus Christ.