2 Peter 3:1

2: False teachers Peter warns that just as there were false prophets in the past, there will be false teachers among them, who will secretly bring in destructive heresies, even denying the Lord who bought them, bringing on themselves swift destruction. Many will follow their destructive ways, because of whom the way of truth will be blasphemed. With covetousness they will exploit the believers with deceptive words. Their judgment has not been idle, and their destruction does not slumber. Peter provides historical examples of God's judgment: He did not spare the angels who sinned, but cast them down to hell; He did not spare the ancient world, but saved Noah, a preacher of righteousness, while bringing in the flood; and He condemned the cities of Sodom and Gomorrah to ashes, making them an example, while delivering righteous Lot, who was oppressed by the filthy conduct of the wicked. The Lord knows how to deliver the godly out of temptations and to reserve the unjust for the day of judgment. These false teachers are described as presumptuous, self-willed, and not afraid to speak evil of dignitaries. They are like natural brute beasts made to be caught and destroyed, who speak evil of the things they do not understand. They have eyes full of adultery, are experts in covetousness, and have forsaken the right way, following the way of Balaam. They are wells without water and clouds carried by a tempest, for whom is reserved the blackness of darkness forever. They speak great swelling words of emptiness, and while they promise liberty, they themselves are slaves of corruption. Peter concludes with a stark warning: it would have been better for them not to have known the way of righteousness than to have known it and then turn from the holy commandment, fulfilling the proverb, "A dog returns to his own vomit," and, "a sow that was washed to her wallowing in the mire."