1 John 2:19
They went out from us, but they were not of us; for if they had been of us, they would have remained with us; but they went out, that they might be made manifest that they are not all of us.
John 8:44
Ye are of your father the Devil, and what your father desireth ye are ready to do. He was a murderer from the beginning; and he abideth not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh from his own nature; for he is a liar, and the father of it.
2 Corinthians 6:15
And what concord hath Christ with Beliar? Or what part hath a believer with an unbeliever?
1 John 3:10
In this are manifest the children of God and the children of the Devil. Whoever doeth not righteousness is not of God, and he that loveth not his brother.
Jude 1:19
These are they that separate themselves, sensual, not having the Spirit.