Know you not that your bodies are the members of Christ? shall I then take the members of Christ, and make them the members of a harlot? God forbid.
All Commentaries on 1 Corinthians 6:15 Go To 1 Corinthians 6
Cyprian of Carthage
AD 258
Or know ye not that he who is joined together with an harlot is one body? for two shall be in one flesh. But he who is joined to the Lord is one spirit.".
Hence also he says the same thing: "That the members of Christ must not be joined with the members of an harlot."