1v10 Who am I trying to please

For am I now seeking the approval of man, or of God?
Or am I trying to please man?
If I were still trying to please man, I would not be a servant of Christ.

On the face of it this is a restatement of Jesus' own words on how we can only have one master. God or money. 'No other gods before me'. Christ or people. It's absolutely true, question is what's it doing in Galatians? It doesn't need to be to establish it since it's already in God's word.

A developing issue in Galatians is an accusation that Paul is the scorned lover of the Galatians. Sure they started with him but now they've found some other teachers to follow, and he's just writing because he's jealous, disappointed etc. Here and over the rest of chapter 1 Paul is determined to show that his allegiance is to Jesus and the gospel and therefore to people, rather than to people because of his own ego.

The other side of the equation is that he'll accuse the false teachers of being people pleasers (ch4) who are zealous for the Galatians for the sake of their own reputations (ch6). Zeal is great. Passion is great. But like faith the key issue is what's the object of it. Zeal for pleasing people is worthless. Zeal for the gospel is glorious.

The interests of Christ coincide with what is best for the Galatians and so he does appeal to them passionately and in bewilderment at their change of direction. Not because he wants their approval but because he wants them back with Jesus. They might mistake his concern for being concern for his own followings, or for them - but they should see that it is his passion for Jesus that leads him to this gospel care.

The gospel always does this. It drives Christians to reach others because of our passion for Jesus. It drives Christians to care for other Christians, to keep them enjoying the benefits of the gospel and so bringing glory to Jesus. The best interests of the gospel coincide with the best interests of people, though it doesn't always seem that way to foolish human thinking, which is something the Galatians are slipping into (3v1).