But there could be no greater mistake. The doctrine of justification by faith alone apart from the works of the Law appears indeed in the Epistle to the Galatians as a weapon against the Judaizers. But why was Paul opposed to the Judaizers in the first place? Certainly it was not merely because the Judaizing demand that Gentile Christians should be circumcised and keep the Law would interfere in a practical way with the Gentile mission. Paul was not like some modern leaders of the Church, who are interested in mere bigness; he was not interested in the extension of the Church if such extension involved the sacrifice of principle. Nothing could be more utterly unhistorical than the representation of Paul as a practical missionary, developing the doctrine of justification by faith in order to get rid of a doctrine of the Law which would be a hindrance in the way of his Gentile mission. Such a representation reverses the real state of the case. The real reason why Paul was devoted to the doctrine of justification by faith was not that it made possible the Gentile mission, but rather that it was true. Paul was not devoted to the doctrine of justification by faith because of the Gentile mission; he was devoted to the Gentile mission because of the doctrine of justification by faith. And he was opposed to the Judaizers, not merely because they constituted a hindrance in the way of the Gentile work, but because they made the cross of Christ of none effect. "If righteousness is through the law, then Christ died in vain" (Gal. ii. 21). These words are at the very heart of Paul's life; for they involve the Pauline doctrine of the grace of God.