Galatians 3:1-5 meaning

Paul preached the gospel to the Galatians; he taught them about Christ's death. Through his evangelizing, Jesus was publicly portrayed as crucified to the Galatians. They knew the gospel. Paul is shocked that they would abandon that truth. It's as if they had been bewitched, like someone had placed a spell on them so that they are abandoning Christ. To demonstrate how crazy these believers are behaving, Paul walks them through the illogical thought process that they have fallen prey to.

First, Paul asks them a simple question: did you receive the Spirit by works of the Law, or by hearing with faith? The question is rhetorical and the answer is obvious. It wasn't by works of the Law (obeying the law of Moses) but by faith in Christ that the Galatians received the Holy Spirit. That of itself proves that the power is in the Spirit received by faith, not following works of the Law.

Paul challenges them, pointing out that they began as believers by the Spirit. In light of that, he asks them, why they would think the Law could perfect them? The word translated "perfect" is from the Greek word epiteléō. It might be better translated "complete" or "mature." The same word is translated "complete" in 2 Corinthians 8:6, "So we urged Titus that as he had previously made a beginning, so he would also complete in you this gracious work as well."

Paul is pointing out that when we are justified by faith through the Spirit, that is our new birth. Like any baby, we now need to grow up to be completed as a new creation. Does it make sense that God would make us a new creation by the power of the Spirit, then grow us up by the law? The Greek word "teleo" is also translated "complete" or "mature"; by adding the "epi" the Greek adds an emphasis, with the sense of being "totally" complete or mature. The point is that we grow up the same way we are born, by faith.

If the Spirit is given to us because of our faith in Christ, why would we think we would now be made complete by another means? Much of the remainder of Paul's letter will be dedicated to exhorting us to walk in the power of the Spirit, in order to be completed, to be fulfilled. It also seems that the competing Jewish "authorities" were somehow connecting the completion of our walk with being justified in the sight of God. He emphasized in chapter 2:

"We are Jews by nature and not sinners from among the Gentiles; nevertheless knowing that a man is not justified by the works of the Law but through faith in Christ Jesus, even we have believed in Christ Jesus, so that we may be justified by faith in Christ and not by the works of the Law; since by the works of the Law no flesh will be justified" (Galatians 2:15-16).

The law does not set us right before God, only faith in the true gospel of Christ can do that. That is why in Galatians 2:17 Paul chastised the Galatian believers for seeking to be justified in Christ by following the Law. Why would you seek what you already have? It makes no sense for those who are already justified by faith in Christ by the power of the Spirit to seek to be justified by some other way (such as following religious rules).

All these things the Galatians knew—they had been taught by Paul. They were introduced to Jesus by Paul. This is why Paul is so upset (calling them "foolish" multiple times and even suggesting that their behavior resembles someone who has been "bewitched"). Paul points out, too, that the Galatians are following these religious rule teachers rather than He who provides you with the Spirit and works miracles among you. The Galatians not only received the Holy Spirit by faith but also saw miracles performed by that same faith in the same gospel message of Christ. If miracles come by the Spirit, doesn't that prove that the power to be completed in Christ will come by the Spirit?