Wolves in the Church - false doctrine has destroyed many
For certain men have crept in unnoticed, who long ago were marked out for this condemnation, ungodly men, who turn the grace of our God into lewdness and deny the only Lord God and our Lord Jesus Christ.
Paul wrote in the early stages of the church: "For I know this, that after my departure savage wolves will come in among you, not sparing the flock." (Act 20:29)
And Peter also wrote: "But there were also false prophets among the people, even as there will be false teachers among you, who will secretly bring in destructive heresies, even denying the Lord who bought them, and bring on themselves swift destruction. And many will follow their destructive ways, because of whom the way of truth will be blasphemed. By covetousness they will exploit you with deceptive words; for a long time their judgment has not been idle, and their destruction does not slumber." (2 Peter 2:1-3)
Jude elaborates: "as Sodom and Gomorrah, and the cities around them in a similar manner to these, having given themselves over to sexual immorality and gone after strange flesh, are set forth as an example, suffering the vengeance of eternal fire." (Jude 1:7)