Galatians 1:9

As we have said before, so say I now again, If any man preacheth unto you any gospel other than that which ye received, let him be anathema. [Here the apostle supposes an impossibility, that he may thereby show that it is not possible to make any alterations in the gospel which God would sanction or accept. No man could make such alterations; no, not even an angel. Chrysostom suggests that these gospel perverters claim for their teaching the authority of the older apostles, Peter, James, John, etc., and interprets Paul thus: "Don't tell me of John, don't tell me of James. If one of the highest angels were to come, corrupting the truth originally preached, he must be rejected.... When the truth is in question, respect of persons is inadmissible." In this connection it is interesting to note that the Galatians had at first received Paul as an angel of light (Galatians 4:14), and they were now probably so receiving these perverters. Also we may observe that the words of angels would be valueless if spoken in an improper spirit (1 Corinthians 13:1), and lastly that the sayings of Jesus differ from the sayings of the law in this very respect, viz.: they are weightier than any words conveyed through the agency of angels (Hebrews 1:2; Hebrews 2:1-3). Upon all such perverters Paul pours out the anathema of God, devoting them to destruction. See 1 Corinthians 16:22. In later centuries the anathema became associated with excommunication, until the two words became convertible terms; but no such confusion of terms existed in Paul's day, and his words mean more even than severance from the church. Moreover, excommunication would not affect angels, since they are not members of our churches. Paul's language shows that at his last visit (Acts 18:23) he had warned the Galatians against such Judaizers, and he now makes the warning more effectual by repetition. His reference to his former words suggests surprise that they should have so far forgotten them as to be misled despite them. The strong wording of this entire passage forms a solemn warning against the sin of corrupting the gospel. All offices, appearances and reputations to the contrary, whoso perverts the divine truth is an enemy to Christ, and rests under the curse of God. Compare Matthew 7:22-23. And who will presume to say how large or important a change must be to constitute a perversion? It is best, as Dean Howson observes, to understand Paul as "precluding any deviation of any kind from the original gospel."]