1 Corinthians 6:15-18 “Do you not know that your bodies are members of Christ? Shall I then take the members of Christ and make them members of a prostitute? Never! Or do you not know that he who is joined to a prostitute becomes one body with her? For, as it is written, ‘The two will become one flesh.’ But he who is joined to the Lord becomes one spirit with him. Flee from sexual immorality. Every other sin a person commits is outside the body, but the sexually immoral person sins against his own body.”
The believer’s body is a member of Christ. How can we be joined to Christ and joined to sin at the same time? When an individual Christian commits sexual immorality, it disgraces the entire body of Christ. The Corinthians saw no harm in visiting the temple prostitutes. Jesus Christ bought us with a price and therefore our bodies belong to Him. We are to yield our bodies to Him as living sacrifices.
The word “joined” actually means to cement or glue together. In their sexual relationship, a husband and wife become “one flesh” in a way that is under God’s blessing. In sex outside of marriage, the partners become “one flesh” in a way that is under God’s curse. Sex outside of marriage ultimately shatters instead of unites.
“When a man and woman join their bodies, the entire personality is involved. There is a much deeper experience, a ‘oneness’ that brings with it deep and lasting consequences. Sexual sin is the most serious sin a person can commit against his body, for it involves the whole person. The sexual experience affects the total personality. Sex outside of marriage is like a man robbing a bank: he gets something, but it is not his and he will one day pay for it. Sex within marriage can be like a person putting money into a bank: there is safety, security, and he will collect dividends.” –Warren Wiersbe
Paul gives us a very simple, very effective prescription for sexual purity. FLEE! Paul doesn’t tell us to be brave and resist the lustful passion of sexual immorality, but to flee from its very presence. Many have fallen because they underestimated the power of lustful passion, or thought they would “test” themselves and see how much they could “take.” Instead we should follow the example of Joseph, who fled from sexual immorality – even when it cost him something to do so.
Paul does not say that Christians should flee sex, only sexual immorality. God gave sex as a precious gift to mankind, and uses it powerfully to bond husband and wife together in a true one-flesh relationship. Hebrews 13:4 says the marriage bed is undefiled – the sexual relationship between husband and wife is pure, holy, and good before God.
Although sexual sin is not necessarily the worst sin, it is the most unique in its character. It drives like no other impulse and when fulfilled affects the body like no other sin. I’ve heard it said by those who have lived an immoral life that you never forget those previous encounters and effects the body’s responses for life.
Illicit sex has a way of internally destroying a person the way no other sin has. Because sexual intimacy is the deepest uniting of two persons, its misuse corrupts on the deepest human level. Sexual sin has a unique effect on the body; not only in a physical way but also in moral and spiritual, psychological ways.