1 Corinthians 6:13
13Foods for the stomach and the stomach for foods, but God will destroy both it and them. Now the body is not for sexual immorality but for the Lord, and the Lord for the body.
This is easily understood. Food is good, but fleeting. We eat one moment and then the next we are hungry again. Many physical things we do are fine and often they have nothing to do with our devotion to the Lord. But sexual immorality is different. Our bodies are to be pure before God. If there is sexual immorality in the church, then it affects the body of Christ. We cannot be dedicated to the Lord and be involved in fornication at the same time.