'Unbeliever' in the Bible

But if the unbeliever leaves, let him leave. The brother or the sister is not bound in such [cases]. But God has called us in peace.

But if all prophesy, and some unbeliever or outsider enters, he is convicted by all, he is judged by all,

And what agreement [does] Christ [have] with Beliar? Or what share [does] a believer [have] with an unbeliever?

But if someone does not provide for his own [relatives], and especially the members of his household, he has denied the faith and is worse than an unbeliever.