11 See with what large letters I have written to you with my own hand!
12 As many as desire to make a good showing in the flesh, these would compel you to be circumcised, only that they may not suffer persecution for the cross of Christ.
13 For not even those who are circumcised keep the law, but they desire to have you circumcised that they may boast in your flesh.
large letters (v.11) — size of the writing, not length of the letter. Paul may have written large because of bad eyesight, for emphasis, or both. We don’t know.
my own hand (v.11) — Paul may have written the entire letter himself or had a secretary write most of it and just added these final sentences. We don’t know. (I think he wrote it all and had bad eyesight, but I don’t know.)
good showing (v.12) = good face — a display of religious zeal
in the flesh (v.12) — in external things — rituals and ordinances
compel — tense indicates a continuing action with undertermined outcome
only (v.12) — as a means to an end
the cross (v.12) — the doctrine of salvation through the cross
those who are circumcised (v.13) — those who advocated circumcision for the Galatian believers — those who were themselves circumcised
not even … keep the law (v.13) — The Judaizers made no attempt to keep the law. They were hypocrites.
boast in your flesh (v.13) — boast of their accomplishment.
The Judaizers were using the Galatians for the purposes of 1) avoiding the persecution of devout Jews who sought to wipe out the church, and 2) to earn points for themselves. If the Judaizers showed zeal for following the law, they wouldn’t be persecuted as Christians.
What was the motive at work in the mids of the party of the circumcision? It was certainly not concern for the spiritual welfare and the eternal safety of the believers. On the contrary, the motive the apostle discerned behind their zeal was that they themselves might escape the consequences inseparable from the preaching of the Cross, which pronounces accursed not only man the sinner, the lawbreaker, but man the religious law keeper as well. The Cross is thus an offense to Jew and Gentile alike. The addition of something as a means to, or as a condition of, salvation (such as circumcision in apostolic days, or the sacraments in later times) to the free umerited grace of God mediated by faith in Christ alone, has proved the most effective way of avoiding that offense. But to preach a gospel without the Cross is to preach what is no gospel at all. — Galatians, by W.E. Vine, page 268