'Sever' in the Bible

“So come out from among unbelievers and be separate,” says the Lord,“And do not touch what is unclean;And I will graciously receive you and welcome you [with favor],

and every spirit that does not confess Jesus [acknowledging that He has come in the flesh, but would deny any of the Son’s true nature] is not of God; this is the spirit of the antichrist, which you have heard is coming, and is now already in the world.