Followers of Jesus face a constant battle between our flesh and the Holy Spirit. It is inevitable while we live in this cursed world with a natural sin nature. We might want to do all that Jesus wants us to do, but our sin nature fights back with its lusts of the flesh, lusts of the eyes and the pride of life. Many think that lust is simply unbridled sexual desire, but the original definition was a strong persona inclination or intense longing. Lust could apply to sexual desire but can also be applied toward anything that becomes an obsessive desire. Examples might be power, wealth, revenge, food, alcohol, drugs, or even attention.
Paul viewed his physical body as a sparring partner. The goal with a sparring partner is to control and overcome. The goal of the sparring partner is to discover and expose weakness. Paul wrote that he disciplined himself. He controlled his body rather than his body controlling him. This battle takes place in the mind.
When we belong to the Lord Jesus, we must remember that our bodies are not our own. We have been bought with a price and that price was the life and blood of the Jesus (I Corinthians 6:19-20). We must remember and obey his challenge to present our bodies as living sacrifices and be transformed by the renewing of our minds (Romans 12:1-2). We must always remember that as we yield ourselves to God, our bodies are to become instruments of His righteousness (Romans 6:12-13). We must remember that the self-control needed to discipline our bodies is part of the fruit of the Holy Spirit (Galatians 5:22-23). It is a daily battle that requires total submission to the only One Who can empower us to overcome the lust of the flesh, the lust of the eyes, and the pride of life. For further reading, check out I Corinthians 8:6; 9:19,22, and 27.