Paul has some parting words for the Galatians. Hey, if there's one thing Paul loves, it's giving advice.
If a fellow Christian sins, then everyone else should help him or her to get back on the straight and narrow. Remember, says Paul, we're all imperfect, so cut those sinners some slack.
But also keep in mind that you're doing the right stuff personally. Don't be arrogant and do your fair share in the community.
If you're taught something good, then pass it on.
Paul also reminds them that they "reap whatever [they] sow." This sounds familiar. Basically, he just means that if you plant seeds of goodness and love in your life, that's what will grow. But if you toss some bad seeds on the ground, your harvest will not be pretty at all.
End of Rant
Paul closes by telling them to keep the faith and not listen to his opponents around Galatia.
He suspects that these naysayers just want Gentiles to get circumcised so they can brag about how awesome and convincing they are all over town. They don't really even care about the law that much because they don't actually follow it themselves. Oh, burn.
Paul, on the other hand, doesn't roll like that. The only thing he ever brags about is Jesus's crucifixion. Paul, we're not sure you're doing this whole bragging thing right.
He ends the letter by reminding them that it doesn't matter whether you're circumcised or not. All that matters is that you've been born anew in Christ.
The only physical marks that matter to Paul are the ones he got in the service of Jesus. Paul had a knack for getting almost stoned to death quite a bit.