Those who demand circumcision are saying, “God wants you to be a Son of Abraham!”
“That’s true,” Paul replies. “But which son?”

Paul starts off nicely enough, but quickly begins to sputter curses and then launches into his personal testimony.

Paul gets into the meat of his message: God’s law is great, God’s law is good, but it could never transform you into God’s child. So why oh why are you trying to use it that way now?