Note 10 at Gal. 4:17: The NIV translates this verse as, "Those people are zealous to win you over, but for no good. What they want is to alienate you (from us), so that you may be zealous for them." This seems to accurately represent what the old King James English is trying to convey.

Paul has addressed the false teachers' gospel and now he is addressing their motives. He is stating that they are zealous, but not in a good way or for a good purpose. Their intention is to alienate the Galatians from the true gospel and from those who teach it, so that instead of the Galatians going to Christ they will come to them (the Judiazers).