What is fornication according to the Bible?

So far we have left out of our consideration the fact that the Lord Jesus here gives room for one exception, which clearly excludes any other exception: "Whosoever shall put away his wife, saving for the cause of fornication..." Yet this one and only exception is missing in Mark 10:11-12 and Luke 16:18. Paul in 1 Corinthians 7 does not mention it either. We only find it again in Matthew 19:9, albeit in a slightly different wording ("except it be for fornication"). The Lord does not say that divorce is unavoidable in the case of one partner committing fornication, but only that in such a case the remarriage of the other partner after a divorce is not adultery.

According to Scripture, the sin of fornication not only refers to prostitution, but to any pre- or extramarital intercourse. We saw this earlier when we considered verses 27-30. Fornication is also adultery when at least one of the persons involved is married. Here the general term, "fornication," is used, although the verse deals especially with adultery. It seems rather far-fetched to interpret "fornication" here as implying immoral behaviour before the marriage, of which the husband learns only after the wedding.

In God's sight immoral behaviour is so abominable that Paul had to write to Ephesus: “But fornication, and all uncleanness, or covetousness, let it not be once named among you, as becometh saints” (Eph. 5:3). This means that we should not mention these things frivolously and so make little of them. The Bible speaks very clearly as to God's judgment about these sins. Holy Scripture not only calls prostitution fornication, but all extramarital intercourse, even where there may be the intention to get married, and even if it is done only once (cf. Gen. 34 and 38). In the world today the word fornication is only used in connection with the first meaning. In the New Testament, however, extramarital intercourse in general is called fornication, that of married persons is called adultery, and both are condemned as abominable sin (Matt. 15:19; 1 Cor. 6:9; Heb. 13:4).

The whole of Scripture is full of the errors of fornication (Acts 15 v 29) and adultery (Exodus 20 v 14). The first is sexual relationship outside of marriage and the second sexual relationship with a married person. We must clearly state that physical affection is only intended by God for one man and one woman and that within the confines of marriage and to a very limited extent by a couple committed to marriage (see previous chapter).

The subject of moral defilement is taken up in 1 Cor. 5. A case of fornication had arisen in the Corinthian assembly. Fornication seems to be a term used in the Scriptures to encompass all kinds of sexual sins. In this case it was adultery-made worse as he was sinning against his own father-incest. Such a person must be excluded by the assembly from all fellowship. A list of similar serious sins is given in verse 11 and again in chapter 6 verses 9-10. These do not seem to be comprehensive, but in 2 Tim 3:2-4 we have another list of those persons from which a Christian must turn away, which seems to fill up any that are lacking.

This was very common among the Gentiles, which accounts for its being mentioned in the message sent from the conference at Jerusalem to the Gentiles, Acts 15:20, 29; and its being so often prohibited in the epistles. The word is sometimes used where 'adultery' is the sense. Matt. 5:32; Matt. 19:9. It often has in the O.T. a symbolical reference to the turning from God to idols. 2 Chr. 21:11, 13; Isa. 23:17; Ezek. 16:15, 26, 29; and in the N.T. to unfaithful intercourse with Babylon, the mother of harlots. Rev. 14:8; Rev. 17:2, 4; Rev. 18:3, 9.

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.

12 All things are lawful to me, but not all things profit; all things are lawful to me, but I will not be brought under the power of any. 13 Meats for the belly, and the belly for meats, but God will bring to nought both it and them; but the body [is] not for fornication but for the Lord, and the Lord for the body. 14 And God both raised the Lord, and will raise up us by his power. 15 Know ye not, that your bodies are members of Christ? Shall I then, taking the members of Christ, make [them] members of a harlot? Let it not be. 16 What! know ye not that he that is joined to the harlot is one body? For, says he, the two [shall be] one flesh. 17 But he that is joined to the Lord is one spirit. 18 Flee fornication. Every sin whatsoever that a man may practise is outside the body, but the fornicator sins against his own body. 19 What! know ye not that your body is the temple of the Holy Spirit that [is] in you, and that ye are not your own? 20 For ye were bought with a price: do then glorify God in your body.

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.

In pronouncing his sentence that Gentile believers are not to be put under Jewish law in any way, James does, however, suggest that the brethren write to Gentiles of three things connected with God's creatorial rights that were too commonly abused among the Gentile nations. They would ask them, first, to abstain from pollutions of idols. To recognize an idol in any way was a direct insult to God, for the idol usurps God's place. Secondly, fornication must be avoided, for this is a serious violation of those relationships God has established for the blessing of mankind. Thirdly, they must not eat things strangled, nor blood, for God requires that the blood of an animal must be shed before the flesh may be eaten. The blood is the life, and we must show this respect for God's rights as the life-giver. Disregard of this is despising God. These things were not merely Jewish laws but were basic in creation from the beginning.

A fornicator is one who is morally corrupt and living in immorality*., Such an one is not fit for the fellowship of saints. A covetous person is one who is greedy of gain and actively seeking to grasp what he has not and desiring to take away what another possesses. Covetousness is an unlawful desire to possess oneself of something in opposition to good morals. "Greedy unsatisfied lust" or "unbridled lust" is a good rendering of the word "covetousness." (See Eph. 5:3 and Col. 3:5, New Trans.). One whose course of conduct is characterized by such unbridled desires and lust for that which does not rightly belong to him, should be put away as a wicked person. Covetousness is idolatry according to Colossians 3:5.

When Potiphar's wife desired Joseph to lie with her and commit fornication, he replied, "How then can I do this great wickedness and sin against God?" (Gen. 39:9) One act of fornication or adultery was great wickedness to Joseph and is such before God. It begins with lusting after another and committing adultery in the heart, (Matt. 5:28) and then the actual sin follows.