Gal 6

Verses 11 to 18

If Paul has dictated this letter to a scribe, v. 11 becomes an authenticating mark in his own hand. Which can only work if someone receiving the letter would recognise Paul's large letters.

Paul ends this letter with the contrast between making a show in the flesh and holding fast to the cross of Christ. Circumcision has this value, you can measure it. You can boast of it. You can do neither with the cross of Christ.
It is claimed that by circumcision the law is kept, however, the whole law is not kept or even attempted.

A Christian's boast is in the cross of Christ - note, not the Christ upon the cross, but the cross of Christ. In union with Christ we die, we die to the world and its poor, selfish desires. Under the cross we are like those who are dead to the world.
Paul is not arguing that uncircumcision is better than circumcision. The new creation which follows the cross is everything.

There will be peace and mercy upon all who are in union with Christ and who cling fast to the cross.