Galatians 6:17 From henceforth let no man trouble me: for I bear in my body the marks of the Lord Jesus.
18 Brethren, the grace of our Lord Jesus Christ be with your spirit. Amen. (To the Galatians written from Rome.)
Paul is finishing this letter to the Galatians by letting them know he bore many stripes, because he would not renounce Jesus Christ as Messiah. He wanted to assure them again, whether they believe him or not, his message brought to them was as an apostle of God. He is saying he does not need their confidence in him to let him know he belongs to Christ. Even Paul’s final benediction implicitly extols the superiority of the gospel of grace over any man-made system of works righteousness. The one word is grace Paul speaks to their spirit man and asks grace. “Amen” means, so be it.