Galations 3 is a story about Paul's astonishment in the people because they kept placing themselves back into the ways works-righteousness instead of the new covenant of faith in Jesus Christ.
Paul said, "O foolish Galatians! Who as bewitched you?" He could not believe that the people would even want to turn back to relying on keeping themselves holy by the outward way they lived their lives when they had been set free from the law. Paul asked them if they were bewitched, under some sort of spell of a sorcerer!
He asked them: "Did you receive the Spirit by works of the law, or by hearing with faith? Are you so foolish?" To Paul, only fools would turn back into rules and regulations made to remain holy on the outside, when the law had failed and sin remained on the inside. Paul asked them that after they had received the Spirit and then turned back to works-righteousness, "Are you now being perfected by the flesh? Did you really suffer so many things in vain?"
Paul said that the same God who Abraham believed by faith and was considered righteous had sent His Spirit to them. That Spirit had done so many miracles among them by His Spirit. He asked them, "Do these same miracles come by the works of the law?"
Paul said that those who live by faith are the sons of Abraham. The Scripture foretold that God would justify the Gentiles by faith, and preached the gospel of Jesus Christ to Abraham when the Word said, "In you shall all the nations be blessed." Those who live by faith instead of works-righteousness are the blessed this scripture describes. They are blessed along with Abraham, the man of faith!
On the other hand, those who rely on works of the law are under a curse! Paul said that it is written in the scriptures, "Cursed be everyone who does not abide by all things written in the Book of the Law and do them"
Now it is evident that no one is justified before God by the works, the things that the flesh can do to become holy. The righteous shall live by faith. The law is not of faith, and living by the law, we can only be justified if we keep each and every one of them!
Christ redeemed us from the curse of the law by becoming a curse for us! Paul said it was written in the scriptures, "Cursed is everyone who is hanged on a tree." Christ is the blessing of Abraham that was foretold to come to the Gentiles. Through Christ, we can now receive the promised Spirit through faith!
As Christians, we should ask ourselves: Do we receive our righteousness by faith in Jesus Christ, or have we fallen back into works-righteousness? Why would we ever want to turn back to laws that are a curse, when we are to be the blessed? If Paul were to come today, would he be astonished at us? Would he call us foolish or bewitched? Have we even accepted the new covenant of Grace?