Paul is concerned for the Galatians because the Jesus PLUS gospel preached by the Judaizers is a false gospel. The True Gospel—the one preached by Paul and the other Apostles is this: we are saved from our sins and spared from the wrath of God by grace alone through faith alone in Christ alone. Thus, Paul’s question: “Who cut in on you?” The Galatians were running well, but were being persuaded to veer off to follow a different Jesus by following a different gospel.