"Whosoever ... abideth not in the doctrine of Christ, hath not God." --
2 John 9
They are all antichrists.
"For many deceivers are
entered into the world, who confess not that Jesus Christ is come in the
flesh. This is a deceiver and an antichrist." -- 2 John 7
They should be shunned. Neither marry nor be friends with them.
"Be ye not unequally yoked together with unbelievers: for what fellowship hath righteousness
with unrighteousness? and what communion hath light with darkness? And what concord hath
Christ with Belial? or what part hath he that believeth with an infidel? ... Wherefore come out
from among them, and be ye separate, saith the Lord."
-- 2 Cor.6:14-17
They should be killed.
"If thy brother, the son of thy mother, or thy son, or thy daughter, or the wife of thy bosom,
or thy friend, which is as thine own soul, entice thee secretly, saying, Let us go and serve other
gods, which thou hast not known, thou, nor thy fathers; Namely, of the gods of the people which are
round about you ... Thou shalt not consent unto him, nor hearken unto him; neither shall thine eye
pity him, neither shalt thou spare, neither shalt thou conceal him: But thou shalt
surely kill him; thine hand shall be first upon him to put him to death, and
afterwards the hand of all the people. And thou shalt stone him with stones, that he die." --