Acts 20:17,28-30, "And from Miletus he sent to Ephesus and called to him the elders of the church...I know that after my departure savage wolves will come in among you, not sparing the flock; and from among your own selves men will arise, speaking perverse things, to draw away the disciples after them."
1 Timothy 1:18-21, "fight the good fight, keeping faith and a good conscience, which some have rejected and suffered shipwreck in regard to their faith. Among these are Hymenaeus and Alexander"
2 Timothy 2:16-18, "But avoid worldly and empty chatter, for it will lead to further ungodliness, and their talk will spread like gangrene. Among them are Hymenaeus and Philetus, men who have gone astray from the truth saying that the resurrection has already taken place, and thus they upset the faith of some."
1 Timothy 4:1, "But the Spirit explicitly says that in later times some will fall away from the faith, paying attention to deceitful spirits and doctrines of demons"
1 Timothy 6:20-21, "O Timothy, guard what has been entrusted to you, avoiding worldly and empty chatter and the opposing arguments of what is falsely called knowledge-which some have professed and thus gone astray from the faith."
2 Peter 2:1, "But false prophets also arose among the people, just as there will also be false teachers among you, who will secretly introduce destructive heresies, even denying the Master who bought them, bringing swift destruction upon themselves."
2 Peter 3:17, "You therefore, beloved, knowing this beforehand, be on your guard lest, being carried away by the error of unprincipled men, you fall from your own steadfastness."
2 John 8-9 "Watch yourselves, that you might not lose what we have accomplished, but that you may receive a full reward. Anyone who goes too far and does not abide in the teaching of Christ, does not have God; the one who abides in the teaching, he has both the Father and the Son."