Why is sexual immorality described as sin against your own body (1 Corinthians 6:18)?

Verse 17. "But he that is joined unto the Lord is one spirit." God, who had said of old, "Two shall be one flesh," now makes a second declaration of the spiritual oneness of the Lord and His redeemed. Creation and its ordinances are a standing analogy of grace. The woman is both of and for the man. The believer is both of and for the Lord. The Sanctifier and the sanctified are all of one.5 It is by faith that we are thus united — married to Him that is risen from the dead, that we may bring forth fruit unto God.6 He had already said, "The body is for the Lord, and the Lord for the body."7 Now, addressing not so much their conscience as their faith, he reminds them of the vital union which subsists between the Giver and the receivers of eternal life. As Adam is in every natural man, so Christ is in every spiritual man. This subject, together with others concerning idolatrous defilement, and the relation of the sexes in the Church of God, will receive a fuller treatment in the following chapters, where they are handled separately and in detail. At present the apostle is intent on the eradication of that particular form of evil which, through a specious abuse of the principle of Christian liberty, was seeking for itself a permanent shelter in the house of God. Accordingly he returns to this in the following verse.

Verse 18. "Flee fornication," etc. Instead of being regarded as a thing indifferent, or even as a trivial offence, this sin is to be dreaded and shunned as a leprosy; for it contaminates both soul and body. Other sins did so but in part; but this completely, by turning that which God has claimed for Himself to an use which He condemns. A wrong is thus inflicted on the body itself, by alienating it from its true honour as an instrument of righteous worship, and again degrading it to the service of sin. It is, therefore, morally, what idolatry is spiritually; and the dissuasive from both is expressed by the apostle in the same terms.8 Each sin is to be fled from, by those who would please God. But there is a further and especial sense in which a believer's body is said to be sinned against by such an act. And this also the Corinthians should have known.

Verse 19. "What? know ye not that your body is the temple of the Holy Ghost?" There is such a thing as spiritual self-respect. A Christian is expected to forget his first parentage in the remembrance of the second. He is not God's creature only, but His child. As the Son of God became incarnate, to put Himself within reach of our sins, so the believer, who adds knowledge to his faith, should understand that his mortal body is the temple of the Holy Ghost. Sent down by the Father in the name of Jesus, He occupies this earthly house as a pledge and witness of its coming change.9 Now it is God's Spirit which we have of Him, and God's Spirit is His own essential presence. But what God dwells in is His temple. We have in this verse a distributive repetition of the doctrine already stated in an earlier chapter.1 Each Christian body is a temple of the Spirit, even as the collective assembly of saints is His temple, and the place where His honour dwells, in what locality soever that assembly is found. Now what God occupies is His, and not our own. We are not robbed of our natural ownership, but it merges in the higher honour of our calling. Our bodies are His temple — ours, therefore, only as ourselves are His; to be kept then, in sanctification and honour, in His Name.2 Thus a double duty is imposed on the Christian with respect to his own body. He is to manage and govern it with vigilance and godly decision, as a restive and unruly beast; he is to hold it in honour, and tremble to abuse it, because it is the temple of the living God. Are we Christians, and yet ignorant of these things? Once more, then, let the cross be our monitor and shame.

Verse 20. "For ye were bought with a price: therefore glorify God in your body." Redemption to God by the blood of His own Son is the "ultima ratio" of all true Christian morality. Our bodies are the property of Him who has purchased us at such a cost; for He did not buy us partly, but entirely. Let, then, the God of our mercy have the willing service of those bodies which are His.3 The fleeting days of our sojourn here below are our opportunity of glorifying Him, by yielding ourselves to Him as those that are alive from the dead, and our members as instruments of righteousness unto God.4

It is not merely that our spirits go to be with the Lord in heaven; our bodies shall be raised like His at His coming, as many bodies of the saints which slept arose and came out of their graves after His resurrection. For if death shows man's weakness, resurrection displays God's power. The actual spiritual effect of this is immense. Not our souls but our bodies are declared to be members of Christ. Those who descant on the soul only may claim a superior elevation. But it is never really so in practice or in theory. On the contrary the immortality of the soul is easily perverted to man's pride; not so the resurrection, which not only exalts God and humbles man but delivers from present ease and indulgence where it is held in faith. Of this the Holy Spirit is the earnest, who joins us to the Lord and constitutes our bodies members of Christ. Hence the enormity of fornication. (Vers. 15, 16.) How basely inconsistent with such intimacy, yea union, is impurity with a harlot! It was the more needful to urge this on a city more than any other noted for this sort of licence, besides the broad fact that the heathen in general regarded fornication as an indifferent act like eating and not as in itself a sin. "The two, says he, shall be one flesh; but he that is joined to the Lord is one Spirit." (Vers. 16, 17.)

But its incongruity with our relation to Christ is not all that the apostle urges. Fornication he would have avoided earnestly, because of its peculiar character, differing as it does from every other sin in this that it is against the body itself, while others are external to it. How dreadful then to think not merely of the body so misused, but the Christian's body, temple of the Holy Spirit as it is! not from any mere consecration to Him but from His being in us, and this from God, on the ground of purchase by Christ's blood. Therefore the apostle's appeal to glorify God in their body.

Indeed, as God raised up the body of the Lord Jesus from among the dead, so will He raise up our bodies. The care of our bodies then is in the power of His own hand, and it is for us now to use them rightly, not to abuse them. In fact, the striking statement is made that "our bodies are the members of Christ." What a dignity is this given to the body! In its present state, of course, it is subject to decay and death, but this is only temporary, and it is to be honorably and properly treated for the Lord's sake. How grossly wrong to take the members of Christ and make them the members of an harlot! It is a practical denial of what is actually true. In practice the joining of two bodies together makes them one, as God declared when He created the woman for the man. "But he that is joined unto the Lord is one spirit." It is a higher, more precious, and eternal unity, and though spiritual, yet the believer's body is to share in this blessing for eternity.

"Flee fornication." In this one is not told to fight, but to keep far from it, as Joseph fled from the wife of Potiphar. Other sins may not involve the body in this way, but this is sin against one's own body. And as well as our bodies being the members of Christ, now we are told, "Your body is the temple of the Holy Ghost." The Spirit of God dwells within our body in order to display in us the precious reality of His character in our practical lives. Notice that it is not said that our spirits or souls are His temple, but our bodies. So that when we are told, "Ye are not your own," we cannot regard this as being merely in regard to our spiritual interests, but fully applicable to our bodies. Being bought with a price - a price so infinitely great - certainly we are totally the property of the Living God; and it is only right and becoming that we should glorify God in our body.

As to justification in the sense in which we have it here, we find it once again in the first epistle to Timothy, where it is said of Christ that He was justified in the Spirit, the Spirit of God as coming upon Him being the witness to His absolute perfection. His was an anointing without blood; ours, on the contrary, is because of the value of that precious blood with God. Thus, then, the soul is brought into freedom. The law has not accomplished this, and therefore he speaks for a moment here of the entire liberty from law which thus results. "All things are lawful to me" does not, of course, for a moment change eternal moral conditions, but has reference to restrictions which were ceremonial merely. "Meats for the belly," as he says, and "the belly for meats." As to these things, there was the fullest and most absolute freedom; and yet even here there might be things inexpedient, and the apostle refuses to be brought under the power of things that are lawful. This is an important matter for our own guidance, for it may well be that that in which we loosely allow ourselves within the range of things entirely lawful may nevertheless have a sorrowful effect upon us. We have to use everything with the wisdom of God, and in our conduct with regard to others in an especial way are not to maintain our own rights, but to seek to minister to the needs of others. These were all things, as he shows us, of a merely temporary nature. Food was necessary in the meanwhile for the life that is, but it will come to an end and that which sustains it. On the other hand, there were things, — and the Corinthians needed the warning, — things which for the heathen in his darkness had little of real evil, but which, brought once into the light of Christianity, were seen in their true character; yet, after all, the power of bad habits might revive, even in the Christian. and thus he has to warn them that the body is simply for the Lord and the Lord for the body. God has already raised up the Lord, and we are to be raised up. In the meanwhile the body will betray us, if we do not take care to govern its appetites. But how wonderful that it is in the body of the believer that the Spirit of God has His abode! "Your bodies," says the apostle, "are members of Christ." This is a different mode of speech from that which we find elsewhere. It is not that believers simply are members of Christ, members of His body, but that our bodies are His members. They belong to Him and are to be used for Him. The body is in the world, that by which we maintain our connection with external things, and in which, therefore, the mind of the human spirit is manifested. Now it is the Spirit of God that has control; the body, as we have been taught in Romans, being simply to be offered up to God as "a living sacrifice, acceptable to Him through Jesus Christ." Our members are to be His members, expressing His mind in lives devoted to Him. "Shall I then," he says, "take away," as the word is, "the members of Christ, and make them the members of a harlot? Far be the thought!" He refers to the Lord's words in Genesis to show how really this would be taking away the body from the Lord. Every other sin, he says, that a man may practise is without the body, does not compromise it in the same way. Gluttony, for instance, or any kindred thing, evil as it is of course, yet after all does not take the body away from Him, and put it in the hands of that which is contrary to Him. With the sin in question, this was in fact what was done. The man sinned, therefore, against his own body. "Know ye not," he says, "that your body is the temple of the Holy Spirit which is in you, which ye have of God, and," as the result of it, "ye are not your own, for ye were bought with a price? Glorify God, therefore, in your body." There are readings here which evidently have come from the thought that this was, after all, altogether too meagre a statement; but if the body be indeed kept in this way for God, if He be glorified in it, if this be really carried out, the whole life must of necessity be His. Our life is in the body; and to have control of the body is to have the life governed for Him. Thus it may be that the body is spoken of as the temple of the Holy Spirit, and not the spirit as His temple, which one would rather expect. It is a triumph of divine grace indeed that here where even as yet the power of redemption is not known, for "we wait for the adoption, that is, the redemption of the body," yet, through the work of Christ, the Spirit of God can dwell in us. How thoroughly that shows He is the witness to Christ's perfection, to the perfection of His blessed work, and not to any perfection of our own; and here, where the contact with the world is seen in the fullest way, the Spirit of God is found to deliver us from the evil influences of that contact. The anointing oil, as we may say, flows from the head down to the hem of the garment.

Verse 15. "Know ye not that your bodies are the members of Christ?" etc. What they will be in their final transformation they already are in truth. They should have known this also. For the faith which unites us to the living and ascended Lord does not disjoin us from ourselves. If we are redeemed men, our bodies (though not yet fashioned to their destiny) are as surely our Redeemer's as our souls.1 As a natural man, the believer is not divided, but judicially extinct. "Ye are dead," 2etc. As a member of Christ, he is inhabited by the power which will presently transform his body to the likeness which belongs to the life which he already has by faith. It was, then, a foolish imagination to suppose that the soul and body could be under different rules. Both are the Lord's, though each has its proper functions and its own relation to the other. The quickened soul is the appointed ruler of the unchanged body. Now the desire of the new man is holiness, while the predisposition of the body is to the service of sin. But to the will of the new man there is added also the enabling power of the Spirit which dwells in us; and it is on this distinctive truth that proper Christian responsibility is founded. The apostle, therefore, who through grace so justly apprehended his position as a man in Christ, and stood so jealously upon its honour, exclaims: "Shall I take the members of Christ?" etc., and answers his own question with an instant and vehement denial. But might there not be (in the estimation of some philosophizing Christian) a tinge of extravagancy in the language here employed? If any thought so, they must submit to still further teaching on this point.3

Verse 16. "What? know ye not?" etc. Had they forgotten that He who made them at the beginning made them male and female, that by a natural union they might, though twain, be yet one only in His eyes? Fornication is nature without God. It is therefore sin, like every other act of God-forgetting wilfulness. But in a Christian it is doubly sin; for what he does, he does as a member of Christ's mystic body. He cannot abdicate the honour put upon him by the grace of God, though by a careless walk he may deny his own confession, and grieve that Holy Spirit of God by which he has been sealed unto the day of redemption.4

The Apostle then passes on to speak of that which is not lawful for the body — actual sin. Here we are reminded that the body is for the Lord, and the Lord for the body. He reminds us, too, that these bodies are destined for high honour, for even as God has raised up the Lord, so will He also raise up these bodies by His own power. Moreover, our bodies are members of Christ, and he that is joined to the Lord is one Spirit. The Apostle learnt something of this great truth at his conversion, for the Lord said to him, “Why persecutest thou Me?”. To touch the bodies of the saints was to touch Christ. How solemn is all sin, but how specially solemn is sin against the body which is indwelt by the Holy Spirit and belongs to God, and which it is our privilege and responsibility to use for the glory of God. To press upon us the deep importance of holiness, the Apostle reminds us in the course of the chapter that we are washed, sanctified and justified, and further, that our bodies are for the Lord, joined to the Lord, indwelt by the Holy Spirit, belong to God, and are to be used for the glory of God; and, too, the Lord is for the body, and God will raise it up by His power.

The next, and very solemn use that is made of this gift of the Spirit, is as regards the believer's body. It is not now that together Christians constitute the temple of God, but that each one's body is His temple. This is a capital truth of Christianity; for the Corinthians fell into that error which has been perpetuated in our own day, that, if we be only right in heart, it matters not about the body — that we must not be too particular as to outward things, among which comes, of course, the body as the outward instrument of the man. To such it seemed an unspiritual thought to be occupied with the body: why not insist on the inner man? Let the soul be right, and the rest may be safely left. Not at all, says the apostle Paul; the Holy Ghost is pleased to dwell in the man, and makes, not the soul, but the body, His temple. If the body is consecrated to the Lord, if it is separated by the power of the Holy Ghost, the soul must surely be all right. But there might be excuses made, so as to leave the body free for self-indulgence and downright wickedness, while highflown sentiments filled the spirit of a man. This, it is evident, is hateful to God. "Ye are bought with a price: therefore glorify God in your body." (1 Cor. 6)

But there are deeper things prefigured. The apostle refers to these words both in 1 Cor. 6 and in Eph. 5; and each is of the highest interest and importance, though the one he individual, and the other corporate. The fleshly union, shameful out of marriage, God would have honourable under marriage, honourable in all things (Heb. 13:4); for even the married are gravely exhorted, as the licentious are solemnly warned. But that union is used and meant to remind the Christian of his own blessed privilege: he that is joined to the Lord is (not one flesh but) one spirit. It is indeed in virtue of his receiving the Holy Spirit. Thus is impurity shown to be a sin not only against his own body, but against the Trinity and the price paid. "Glorify God then in your body." The corporate reference is no less striking. "Christ loved the church and gave Himself for it," not merely to sanctify it, purifying by the washing of water in the word, but to present it to Himself glorious, the Eve of the Second Man, the Last Adam. Hence He meanwhile nourishes and cherishes it; for we are members of His body. Thereon our text is cited, with the appended comment, "This mystery is great, but I speak as to Christ and as to the church." In no way does it yield the paltry sense of "sacrament" which Romanism has drawn from the Vulgate mistranslation, though not without the protest of such as Cajetan and Estius. Holiness is therefore as incumbent on the church as on the christian; and the Holy Spirit abides in the one as in the other to secure it, and to make the sanction of evil inexcusable in either.

But the doctrine that the body is for Christ decided another question, to which the depraved habits of the Corinthians gave rise. All fornication is forbidden. To us, with our present Christian habits of mind, it is a thing of course — to Pagans, new; but the doctrine exalts every subject. Our bodies are the members of Christ. Another truth connected with this is of great importance: if (by union according to the flesh) two were one body, he who is united to the Lord is one spirit. The Spirit whose fulness is in Christ is the same Spirit who dwells in me and unites me to Him. Our bodies are His temples. What a mighty truth when we think of it!

Moreover we are not our own, but were bought with a price — the blood of Christ offered for us. Therefore we ought to glorify God in our bodies, which are His — powerful and universal motive, governing the whole conduct without exception. Our true liberty is to belong to God. All that is for oneself is stolen from the rights of Him who has bought us for His own. All that a slave was, or gained, was the property of his master; he was not the owner of himself. Thus it was with the Christian. Outside that, he is the wretched slave of sin and of Satan — selfishness his rule, and eternal banishment from the source of love his end. Horrible thought! In Christ we are the special objects and the vessels of that love. We have here two mighty motives for holiness: the value of Christ's blood, at which we are purchased; also the fact that we are the temples of the Holy Ghost.

This closeness of union is used elsewhere in the same epistle, not only to set forth the privileges, but also to define the responsibilities, of the believer, and that even as to matters of the most ordinary morality. Amongst those who had recently emerged from a licentious heathenism, considerable doubt might still exist as to how far it was lawful to go in the gratification of their lusts. The question is settled at once by recalling the relationship into which the Christian is brought with Christ. "Know ye not," says the apostle, "that your bodies are the members of Christ?" This determines the whole matter. The unseemliness of using the body for the indulgence of the lusts, becomes manifest the moment it is seen what the believer has become through the baptism of the Holy Ghost, for "he that is joined unto the Lord is one spirit" (1 Cor. 6:15-17). Here the point is, not merely that we "have put off the old man with his deeds, and have put on the new man." This is true, and deeply practical. It implies new creation, a life, not drawn from the first man, but from the second, life of the same order as that of the risen Christ. But the passage quoted from the Corinthians goes beyond this. These believers not only have a new life, a new nature in which Christ "is not ashamed to call them brethren," but they are "joined unto the Lord," so that their very bodies, though not yet redeemed, "are the members of Christ," so divinely perfect is the union into which the Christian is brought with Christ by the baptism of the Holy Ghost.