2 Corinthians 6:14-18 Don’t be unequally yoked with unbelievers, for what fellowship have righteousness and iniquity? Or what fellowship has light with darkness? What agreement has Christ with Belial? Or what portion has a believer with an unbeliever? What agreement has a temple of God with idols? For you are a temple of the living God. Even as God said, “I will dwell in them, and walk in them; and I will be their God, and they will be my people.” Therefore “‘Come out from among them, and be separate,’ says the Lord. ‘Touch no unclean thing. I will receive you. I will be to you a Father. You will be to me sons and daughters,’ says the Lord Almighty.”

1 Corinthians 6:15-20, 7:10-14 Don’t you know that your bodies are members of Christ? Shall I then take the members of Christ, and make them members of a prostitute? May it never be! Or don’t you know that he who is joined to a prostitute is one body? For, “The two”, he says, “will become one flesh.” But he who is joined to the Lord is one spirit. Flee sexual immorality! “Every sin that a man does is outside the body,” but he who commits sexual immorality sins against his own body. Or don’t you know that your body is a temple of the Holy Spirit which is in you, which you have from God? You are not your own, for you were bought with a price. Therefore glorify God in your body and in your spirit, which are God’s. . . . But to the married I command—not I, but the Lord—that the wife not leave her husband (but if she departs, let her remain unmarried, or else be reconciled to her husband), and that the husband not leave his wife. . . . The woman who has an unbelieving husband, and he is content to live with her, let her not leave her husband. For the unbelieving husband is sanctified in the wife, and the unbelieving wife is sanctified in the husband. Otherwise your children would be unclean, but now they are holy.
(Emphasis mine.)