What does it mean that the body is for the Lord and the Lord for the body?
The body is not for fornication but for the Lord, because it was created to bring honor and glory to God. The Lord, in turn, is for the body, making it a two-way street. This contrasts with temporal matters like food and stomach, which God will destroy.
Les explains that 1 Corinthians 6:13 first addresses an everyday physical aspect: food for the stomach and the stomach for food, yet God will destroy both because these belong to our temporal existence. We will not need meals in the new resurrected body. Then the passage moves to sexuality: the body is not for fornication. It was created to bring honor and glory to God. So the body is for the Lord, and the Lord in turn is for the body—a two-way street.
Meats for the belly, and the belly for meats: but God shall destroy both it and them. Now the body is not for fornication, but for the Lord; and the Lord for the body.
More Questions
Why did God create the body?
The body was not created for man to live immorally, but it was created to bring honor and glory to God Himself; that's why He created us.