2 Corinthians 11:13-15
For such men are sham apostles, dishonest workmen, masquerading as apostles of Christ.
Matthew 7:15
"Look out for false prophets, who come to you under the guise of sheep, but inside they are devouring wolves.
Philippians 3:2
Look out for those dogs, those mischief-makers, those self-mutilators!
2 Peter 2:1-3
Now there were false prophets among the people, just as there will be false teachers among you too, who will insidiously introduce destructive heresies and deny the Master who has bought them, thus bringing on themselves swift destruction.
1 John 4:1
Dearly beloved, stop believing every so-called spiritual utterance, but keep testing them to see whether they come from God, because many false prophets have gone out into the world.