Paul makes a number of statements about the state of the Galatians: ‘I am afraid for you, lest I have bestowed upon you labor in vain’ (2:11); ‘I desire to be present with you now, and to change my voice; but I stand in doubt of you’ (2:20); ‘whosoever of you are justified by the law; ye are fallen from grace’ (5:4). But though earlier statements are gloomy and seem to indicate a pessimistic attitude in Paul, this verse shows that his overall outlook concerning them was hopeful.
It is something which stirs up the anger of God when his people are under attack, and every faithful pastor should feel the same protective instincts towards the church of God. Those who do such things can expect the severest possible penalty (Luke 17:2).