He prescribes to flee from fornication as from a kind of persecutor, from whom we cannot be safe for even a single moment, and to strain every effort to abstain from it.
1 Cor. 6:18. Every sin that a man commits is outside the body, but the fornicator sins against his own body.
Fornication, he says, defiles the entire body, which is why those who have committed fornication usually go to the baths as well, testifying thereby that their body has been defiled. Thus the fornicator sins against his own body, defiling and soiling it. Although murder, it seems, is also committed with the body, yet it does not defile the entire body; for one can throw a stone, or a piece of wood, or some other object, but it is impossible to commit fornication without the body: therefore it is always defiled. However, the apostle's intention was to present the gravity of this sin in an exaggerated manner, since his present exhortation concerns it; for fornication is by no means a vice worse than all other vices. I know other explanations on this subject as well. One is the following: the fornicator sins against his own body in the sense that he does not unite for the purpose of producing children, as in union with a lawful wife, but needlessly ruins it by the emission of seed and thereby weakens it. Another explanation: the fornicator sins against the woman with whom he unites, since she becomes his body through this, and therefore if he unites with her unlawfully, he sins against her. However, the explanation of the great John Chrysostom is better than all of them: I mean the first explanation. Furthermore, some raise a doubt and ask: what then? Does not envy also dry out the body? And they resolve this question as follows: envy is a passion, not an action. But the apostle is now speaking of action (for here are his words: "every sin that a man commits"), not of passion. Indeed, envy is not produced by us, but occurs within us.
1 Cor. 6:19. Do you not know that your bodies are the temple of the Holy Spirit living in you, Whom you have from God?
He frightens them even more—both by the greatness of the gift, that is, the Spirit, and by the dignity of the one who bestowed the gift, that is, God. You, he says, are a temple, and moreover a holy one, for you are a temple of the Holy Spirit. Do not defile the holy temple, then, and do not render the gift of God useless; for from God you have the gift and the Spirit.
1 Cor. 6:19-20. And you are not your own. For you were bought with a dear price.
You, he says, are under the Master and have nothing of your own; the body itself is not yours. "For you were bought with a dear price," that is, with the Blood of Christ. Therefore your members are subject to another Master, and to whatever is pleasing to Him, to that you must direct their activity. In saying this, he does not abolish free will, but shows that God, by Whom we have been redeemed, rightfully demands from us service to Himself.
1 Cor. 6:20. Therefore glorify God in your bodies also.
So, since you have been bought, he says, glorify God in your body, that is, by performing good deeds with the body and keeping it holy and pure. For the glorification of God consists in people seeing your good deeds and as a result glorifying Him.
1 Cor. 6:20. And in your souls.
He shows that one must flee fornication not only with the body, but also with the soul, so as not to be defiled even in thought (for by "soul" he meant the mind). In the Gospel (Matt. 5:28) even that adultery which remains only in the heart is forbidden.
1 Cor. 6:20. Which are God's.
You are not your own, he continually reminds, but are under the dominion of God, Who redeemed both our soul and our body.