Look: I, Paul, say to you that if you accept circumcision, Christ will be of no advantage to you. I testify again to every man who accepts circumcision that he is obligated to keep the whole law. You are severed from Christ, you who would be justified by the law; you have fallen away from grace. For through the Spirit, by faith, we ourselves eagerly wait for the hope of righteousness. For in Christ Jesus neither circumcision nor uncircumcision counts for anything, but only faith working through love.
You were running well. Who hindered you from obeying the truth? This persuasion is not from him who calls you. A little leaven leavens the whole lump. I have confidence in the Lord that you will take no other view, and the one who is troubling you will bear the penalty, whoever he is. But if I, brothers, still preach circumcision, why am I still being persecuted? In that case the offense of the cross has been removed. I wish those who unsettle you would emasculate themselves! (ESV)