Be you not unequally yoked together with unbelievers: for what fellowship has righteousness with unrighteousness? and what partnership has light with darkness? And what harmony has Christ with Belial? or what part has he that believes with an infidel? And what agreement has the temple of God with idols? for you are the temple of the living God; as God has said, I will dwell in them, and walk in them; and I will be their God, and they shall be my people. Therefore come out from among them, and be you separate, says the Lord, and touch not the unclean thing; and I will receive you, And will be a Father unto you, and you shall be my sons and daughters, says the Lord Almighty.
(2 Corinthians 6:14-18)