"I am astonished that you are so quickly deserting him who called you in the grace of Christ and are turning to a different gospel - not that there is another one, but there are some who trouble you and want to distort the gospel of Christ."
In this particular instance, Paul was referencing a group of Jewish believers who had come to Galatia and stirred up trouble because Paul had taught the them that they did not need to be circumcised in order to be saved. As Jewish men, they genuinely believed that Jesus was the Jewish Messiah and that if you wanted to enter into Jewish covenant with their Jewish Messiah, you needed to honor their Jewish customs. Not an unfair thought. Fortunately for the Galatians, Jesus came to bring humanity into the actual promise of Abraham, rendering the purpose of the Law void (a blog for another day) In short, circumcision was no longer necessary, neither was becoming a Jew. Jesus was not the Jewish Messiah. He was the Messiah.
Alot of times, we read texts like this and it doesn't really phase us. We think to ourselves, "Well, my mom already decided that for me" or "no one is trying to turn me into a Jew, so this really doesn't apply to me." But friends, it really does, because this same distortion of the gospel is happening today.
How many times do you see someone come into the Kingdom with a deep and pure zeal for the Lord, throwing caution to the wind in their evangelism and worshiping with wild abandon, just desperately in love with Jesus, only to calm down a few months in when people begin to come to them and call their lives into question so often that their focus shifts from the loving of Jesus to the obeying of His commandments?
Really think about that. Because it is not unrighteous to call people into righteousness, but if you pay attention to the fruit of the way a lot of us do that, you'll see that Christians who began zealous and passionate for the Lord quickly make the entirety of their faith obeying God's standards for righteousness. Which is the definition of legalism.
This is the exact same thing that was happening to the Galatians. There is a reason Paul took so much time in the epistles to advise his people that grace does not validate sin. Because the gospel, in its fullness, is freedom. So much freedom that people can become confused and actually believe they have license to do as they please. Its a terrifying concept, but really think about it. At the Cross, Jesus paid the penalty for every sin I would ever commit, meaning that when God forgave me, I could never come into His bad graces again. Because anything I would ever do, I had already received forgiveness for. My sin cannot be held against me (once again, a blog for another day). So repentance from lifestyle choices becomes something that happens as I, within myself, change. Its not something that is beat out of me in shame and guilt. Do we correct each other? Without a doubt! We must, if we love each other. But do we address each others sin in a way that suggests our relationships with God are at stake? No! And when we do, we not only shift believers focus from the face of Jesus to the book of the Law, but we actually distort the very gospel of God. Which Paul kind of suggests is a big deal.
"But even if we or an angel from heaven should preach to you a gospel contrary to the one we preached to you, let him be accursed."
I am in no way suggesting that it is unholy to call people out of their sin. Please do. I am not shy about doing so myself. But I want to caution you to consider how you should do it. When we present our teaching in a way that suggests sin still exists as a barrier between us and intimacy with God, we invalidate the blood of Jesus and call God a liar. Grace may seem too good to be true, but it is still true. At the foot of the Cross, I became free, and to tell me otherwise is to steal Jesus from me. Please don't.