2 Peter 2:1-2
But there were also false prophets among the people, even as there will be false teachers among you; who will privately introduce destructive sects, denying even the Lord who bought them, bringing on themselves swift destruction.
1 John 4:1
Beloved, do not believe every spirit, but try the spirits, whether they be from God; because many false prophets are gone forth into the world.
2 John 1:10
If any one come to you, and bring not this doctrine; receive him not into your house, nor wish him success:
Revelation 2:2
I know your works, and your labor, and your patience; and that you can not bear those who are evil: and you have tried those who say they are Apostles, and are not, and have found them liars;