1 John 2:19
They went away from us, but they were not of us. For, if they had been of us, they would have abode with us; but they went away, that they might be made manifest that they were not of us.
2 Peter 2:1-3
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.
2 Peter 2:18
for, speaking great swelling words of falsehood, they allure by the lusts of the flesh, even by lasciviousness, those who have actually fled away from them who are living in error.
2 John 1:7
for many deceivers are entered into the world, who do not confess Jesus Christ did come in the flesh. This is the deceiver, and the antichrist.
Jude 1:4-16
For certain men have come in privily, who long ago were before written to this very condemnation; ungodly men, perverting the favor of our God to lasciviousness, and denying the only sovereign Lord, even our Lord Jesus Christ.
Revelation 2:6
Yet you have this, that you hate the works of the Nicolaitans, which I also hate.