16 Or do you not know that he who is joined to a harlot is one body with her? For “the two,” He says, “shall become one flesh.” 17 But he who is joined to the Lord is one spirit with Him. 18 Flee sexual immorality. Every sin that a man does is outside the body, but he who commits sexual immorality sins against his own body. (1 Corinthians 6:16–18, NKJV)
These are not pleasant words, nevertheless, their warning is needful. The sexual appetite is strong, and when fed within God-approved marriage, it is undefiled (Heb. 13:4). Every sin we commit begins in the heart (thus, “outside the body”). But, sexual immorality (“fornication,” translated from the Greek word, porneia) is “against the body”, that is, it is opposed to the God-intended purpose of the body (v. 18). After all, your body does not belong to you, but to God (1 Cor. 6:20, 15). Therefore, “glorify God in your body” by fleeing fornication and maintaining sexual purity. Our society is saturated with sexual sins and their allurements. The gospel calls us to the purity of holiness, not to return to the shameful and destructive sins of the flesh (1 Pet. 1:15; 4:1-3). Stolen water is not sweet, and stolen bread feeds the flames of hell (Prov. 9:17-18). While the world indulges itself in this soul-destroying use of their bodies, let us flee fornication and pursue righteousness (2 Tim. 2:22).