if the Ephesian Christians had subtly replaced their love for God and each other with a love for righteousness and right doctrine, the Pergamenian Christians had subtly allowed the erosion of right doctrine in their own midst, while they still held to their faith and trust in Christ.
2 Peter 2: Balaam’s Revenge
It is an exact corollary to what Peter—and Jude—were speaking in such strong terms against. It was the Gnostic cancer, threatening to infect the entire church.