1 Thessalonians 4:3–8 (BE:NT): 3 This is God’s will, you see: he wants you to be holy, to keep well away from fornication. 4 Each of you should know how to control your own body in holiness and honour, 5 not in the madness of lust like Gentiles who don’t know God. 6 Nobody should break this rule, or cheat a fellow Christian in this area; the Lord is the avenger in all such matters, just as we told you before and testified most solemnly. 7 For God did not call us to a dirty life, but in holiness. 8 Anyone who rejects this, then, is not rejecting a human command, but the God who gives his holy spirit to you.
In this passage, Paul uses the Greek word for sexual immorality often translated as fornication. But then he goes on to describe what he's talking about, which appears to be a thing one believer does to harm another, rather than something two believers do together. Is Paul talking about rape here? If not, what is he talking about?