1 Thessalonians 4:3-8

God wants you to be holy and completely free from sexual immorality. Each of you men should know how to live with his wife in a holy and honourable way, not with a lustful desire, like the heathen who do not know God. In this matter, then, no man should do wrong to his fellow-Christian or take advantage of him. We have told you this before, and we strongly warned you that the Lord will punish those who do that. God did not call us to live in immorality, but in holiness. So then, whoever rejects this teaching is not rejecting a human being, but God, who gives you his Holy Spirit.