Romans 16:17-18 : Now I beseech you, brethren, mark them that are causing the divisions and occasions of stumbling, contrary to the doctrine which ye learned: and turn away from them. For they that are such serve not our Lord Christ, but their own belly; and by their smooth and fair speech they beguile the hearts of the innocent. Not all was smooth sailing in that church. Some there were stirring up trouble--causing divisions and occasions of stumbling--contrary to the gospel. Judaizing teachers were the main trouble makers in the territory of Paul's labors; they were determined to convince all Gentile Christians that they had to be circumcised and keep the law, or they could not be saved. They were professed Christians. Likely they had gained some Gentile Christians as helpers. If these disturbers had not reached Rome, Paul knew they would be there. Even today advocates of a modified form of this same theory of Jewish supremacy are troubling churches all over the country. Said Paul, "mark them"--eye them closely. Do not shut your eyes to what they are doing, nor make excuses for them, nor for any others who cause divisions and occasions of stumbling contrary to the gospel, but turn away from them. This means that the brethren should have no fellowship with them. "Contrary to the doctrine which ye learned" covers a wide field, such as mechanical music in the worship, the organization of societies to do the work of the church, and various schemes to raise money. The man who causes divisions in the Lord's church by the introduction of things not taught is an enemy of Christ, even though he may not think so. His interest is in self, and not in Christ. "They that are such serve not our Lord, but their own belly." The more a man appears to be interested in people the more he can deceive--"by their smooth and fair speech they beguile the hearts of the simple"--the trusting and unsuspecting are more easily deceived. The word translated simple does not mean weak minded, but rather, unsuspicious. The deceiver knows how to get the unsuspicious to follow him. People seem never to learn that smooth and fair speech is "the stock in trade" of a deceiver. If he were to announce that he was a wolf in sheep's clothing and that he had come to destroy and not to feed, he would not deceive even the simple. "For even Satan fashioneth himself into an angel of light. It is no great thing therefore if his ministers also fashion themselves as ministers of righteousness" (2 Corinthians 11:14-15). Paul warned the Colossians against being deluded by "persuasiveness of speech" (Colossians 2:4). "And in covetousness shall they with feigned words make merchandise of you" (2 Peter 2:3). From all such we should turn away.