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. 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. As we have said before, so now I say again: If anyone is preaching to you a gospel contrary to the one you received, let him be accursed.
Paul has laid out who he is and how he feels about the gospel. He is enveloped in the gospel more than anyone I can think of, outside of Jesus. He has an understanding of it and a passion for it. He has grasped the concept of grace and it has changed his life. Now he looks at others, and is astonished that they could feel or act differently. How could someone be impacted by an understanding of grace and truth, and give that up to go back to living under some kind of other law? That would be like tasting a my mom's cheese cake, and then going back to store bought.
Paul likens this change of heart to following a different gospel. Not that such an animal really exists as far as God is concerned, but in man's eyes, that is exactly what it is, a different gospel. And it is not a new animal, it is the same old dirty dog that bit you before. But there is a certain level of comfort we have with this old dog.
But for those who return to their old ways, they shall be cursed.Cursed because they have missed the boat and are in danger of hell, but also the curse of living under the law. Because when you live under the law, the only way to satisfy it is to maintain every aspect of it, and impossible task. Paul, as good as he was in his previous lifestyle, surely still realized that he was not perfect. He deeply understood the freedom that grace afforded. And he relished it, and was amazed that some would not.
I want to find that deep of an understanding of grace. I want to grasp the meaning of the gospel message. Don't I? (Yes, I understand there is an inherent risk to that kind of an understanding.)