Galatians 6:12-16 gives background for what Paul was saying in vs 17 and 18. 12 Those who want to impress people by means of the flesh are trying to compel you to be circumcised. The only reason they do this is to avoid being persecuted for the cross of Christ. 13 Not even those who are circumcised keep the law, yet they want you to be circumcised that they may boast about your circumcision in the flesh. 14 May I never boast except in the cross of our Lord Jesus Christ, through which[a] the world has been crucified to me, and I to the world. 15 Neither circumcision nor uncircumcision means anything; what counts is the new creation. 16 Peace and mercy to all who follow this rule—to[b] the Israel of God. It's an outrage to think of how millions of men have been disfigured with that mark. Our faith is our mark.