2 Corinthians 11:13-15
For such men are false apostles, deceitful workmen, disguising themselves as apostles of Christ.
Matthew 7:15
"Beware of false prophets, who come to you in sheep's clothing, but inwardly they are ravenous wolves.
Philippians 3:2
Watch out for the dogs, watch out for the evil workers, watch out for those mutilators of the body.
2 Peter 2:1-3
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.
1 John 4:1
Beloved, do not believe every spirit, but test the spirits to see whether they are of God; because many false prophets have gone out into the world.