Note 10 at 1 Cor. 6:15: All of these verses (i.e. vv. 14-20) are a continuation of the argument Paul gave in verse 12 for holiness (see note 8 at v. 12, this page). Since we are saved by grace, our actions are not essential for salvation. But God forbid that any Christian should take that as a license to sin.

Our bodies are betrothed to the Lord and will someday be resurrected with Him (v. 14). Therefore, we should view ourselves as being married unto the Lord and any action contrary to His Word as adultery. A believer who understands this union should not violate himself and his union with God through sexual immorality.

Note 11 at 1 Cor. 6:15: Paul is saying that we are part of Christ's body. This is what the term "members" refers to. He used this same word to refer to physical parts of the human body (Rom. 6:13, 19; 7:5, 23; 12:4; 1 Cor. 12:12-26; Col. 3:5; Jas. 3:6; 4:1) and believers as being part of Christ's body (Rom. 12:5; here; 1 Cor. 12:12, 27; Eph. 4:25; 5:30).