What The Bible Says About Adultery and Fornication
By Bro David Petersen
Matthew 5:28
"But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart."
Today many Americans are morally confused. They do not have a moral compass to go by. It was not always like this in America. Our country has been on a rapid downhill slide during the last 40 years since the sexual revolution of the 1960's.
Many go by what their own consciences tell them. The conventional wisdom of the age is to "follow your heart". The problem is that our hearts are not good moral compasses. Our hearts will deceive us and lead us astray.
"The heart is deceitful above all things, and desperately wicked: who can know it?" Jeremiah 17:9.
That is why God has provided an absolute moral guidebook: the Bible. God is not about spoiling our fun. He wants us to enjoy life. But since he designed and created us, he knows what is best for us. God gives us his law for our benefit because he loves us. I may not understand why God's law is good for me. But I can still obey it while my understanding is growing.
The truth is that God designed sex for our pleasure, not just for reproduction. But God designed sex to be done only between married couples. All sexual thoughts and behaviors outside of the marraige relationship are either adultery or fornication.
Adultery
Adultery has to do with violation of the marriage covenant. It is sex between a married person and another person with whom they are not married. The seventh commandment prohibited it. "Thou shalt not commit adultery." Under Mosaic Law, when a couple was caught in the act of adultery, both parties were to be killed. (Deut 22:22). Of course this punishment relates only to the nation of Israel under the Old Testament. However the moral principle still applies today.
But Jesus raised the bar when he taught his disciples: "Ye have heard that it was said by them of old time, Thou shalt not commit adultery: But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart." Matt 5:27-28.
Jesus is saying that it is a sin to even look at a woman to lust after her. The sin is committed in one's heart. Wanton lust places the heart in the same sinful condition as actually doing the act.
God's design was that the husband and wife should become "one flesh," each being held sacred to the other. Jesus taught the "one flesh" principle of marraige.
Matthew 19:3-4
3 Some Pharisees came to him to test him. They asked, "Is it lawful for a man to divorce his wife for any and every reason?"
4 "Haven't you read," he replied, "that at the beginning the Creator 'made them male and female,' 5 and said, 'For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh'? 6 So they are no longer two, but one. Therefore what God has joined together, let man not separate."
Let's get the basics here. ONE man and ONE woman. The TWO become one flesh. So the spiritual principle is that two will become one flesh. Not the three, four or more will become one flesh.
Also notice that Jesus said that he created them "male and female", not male and male or female and female. There is no such thing as same sex marraige. He created Adam and Eve, not Adam and Steve! Homosexuality is not the subject of this article. We will take deal with that topic in a later paper. However for now we can say that by Jesus' definition of marraige, that is "male and female", homosexual marraige does not exist. In general homosexuality is a sin that falls under the categories of adultery or fornication which are the subjects of this essay.
As a side note Jesus also discouraged divorce in these verses. "Let man not separate". However in Matt 5:32 he made an exception for when there is fornication. A full explanation of divorce in the Bible is beyond the scope of this article. The main thing to remember here is that the Bible generally discourages divorce except in certain cases.
Very Important! Adultery is not defined by your own personal moral standards. Instead, it is defined by God's absolute law.
God is sovereign and we are not. For example, if both parties of a couple mutually consent to a sexual relationship with some other 3rd party, that does not make it OK with God. It is still a sin. How do I know? I checked with The Manufacturer. He wrote it in his "Owner's Manual", the Bible.
Just because many people in the world have forgotten God's moral law, it does not mean that he has repealed it. God is not taking an opinion poll on this subject and he is not going to ask us all to vote on it. God is still in charge.
Fornication
The term fornication comes from the Greek: “porneia”. We get our English word “pornography” from it. Literally, it means to sell oneself and is thus associated with prostitution. The technical difference between fornication and adultery is that adultery involves at least one married person while fornication is a more general term for sexual immorality that may involve married or unmarried persons. Adultery is a type of fornication are is homosexuality and incest.
I personally struggled trying to make the logical connection between sex outside of marraige and prostitution. I wondered how the idea of selling oneself can be applied when people have the kind of free, casual sex that is so common today. But then it hit me. In essence when unmarried persons have sex they are selling themselves very cheap; for the price of zero and are therefore committing fornication.
In Bible times men usually had to pay one way or another; either by paying a dowry for a wife or by paying a prostitute. Women weren't selling themselves cheap so much like they are today.
But Is It a Sin?
The apostle Paul listed sins of those who will not inherit the kingdom of God. The sins of adultery and fornication were right at the top of the list:
"Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind, nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God." 1 Cor 6:9-10.
So adultery and fornication are definitely sins.
Sometimes saved people will slip into these sins. That does not mean that they lose their salvation. A saved person is securely held by the power of God. They cannot become lost. What this is saying is that willful, practicing adulterers and fornicators will not go into God's heavenly kingdom.
Just in case anybody needs more evidence that adultery and fornication are sins the book of Hebrews says "Marriage is to be held in honor among all, and the marriage bed is to be undefiled; for fornicators and adulterers God will judge." Hebrews 13:4.
About right here is the point in this discussion where a lot of people usually start trying to build a logical argument as to why it's ok. Common arguments are that nobody gets hurt or that that is not what the Bible really means.
The fact is that people do get hurt by adultery and fornication. Besides the obvious STD threat there are the lives destroyed by cheating, the broken families, the lost trust, the feeling of being used and the compulsive behaviors of sexual addiction when people are wholly driven by sexual desire.
When people fornicate they are just using and abusing each other. Oh, there may be some infatuation, but if there is no marraige committment it all just boils down to selfish use. To put it in modern terms looking at someone to lust after them or actually having casual sex with them is 'objectifying' them. It is to treat them as an object instead of a whole person. They become just an object to be used for your personal sexual gratification.
If you are an unmarried woman in a sexual relationship, let me tell ask you this: Why would you let him have the benefits of marraige without the obligtions? Don't you think that you are worth it? Why would you "sell yourself" (porneia) at such a bargain price?
Lastly, a life of sleeping around wears down the body because of the constant biological exposure: "you sleep with everyone your partners have slept with." It's unhealthy and debilitating over time.
Let's not water down the Bible on this topic. It is clear in what it says. Arguments to make it say something else are pointless. "Whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart." That's the Lord Jesus' clear standard. If even looking is a sin, then the doing most certainly is. There's no getting around it. If you don't like what the Bible says on this subject, then as a free will creature you have the ability to rebell, but don't try to make the Bible say something else.
The Woman Caught In Adultery
The account of the woman taken in adultery who, according to the law of Moses, should have been stoned to death reveals the wisdom and grace of Jesus (John 8:3-9). Some Jewish teachers brought a woman to Jesus whom they had charged with adultery. Her accusers said that "she was caught in the very act" so you get the picture of what her offense was. The Lord knew that her accusers were not without sin; and, therefore, they were being hypocrites when they condemned her.
John 8:3-11
3 And the scribes and Pharisees brought unto him a woman taken in adultery; and when they had set her in the midst,
4 They say unto him, Master, this woman was taken in adultery, in the very act.
5 Now Moses in the law commanded us, that such should be stoned: but what sayest thou?
6 This they said, tempting him, that they might have to accuse him. But Jesus stooped down, and with his finger wrote on the ground, as though he heard them not.
7 So when they continued asking him, he lifted up himself, and said unto them, He that is without sin among you, let him first cast a stone at her.
8 And again he stooped down, and wrote on the ground.
9 And they which heard it, being convicted by their own conscience, went out one by one, beginning at the eldest, even unto the last: and Jesus was left alone, and the woman standing in the midst.
10 When Jesus had lifted up himself, and saw none but the woman, he said unto her, Woman, where are those thine accusers? hath no man condemned thee?
11 She said, No man, Lord. And Jesus said unto her, Neither do I condemn thee: go, and sin no more.
Jesus had compassion and mercy on the woman. When Jesus said to her, "Go and sin no more" (John 8:11), He did not excuse her sin; he forgave her of it and warned against continuing in adultery.
Paul also reinforced the "one flesh" concept of marraige in his first letter to the Corinthians.
1 Cor 7:1-5
1 Now concerning the things about which you wrote, it is good for a man not to touch a woman.
2 But because of immoralities, each man is to have his own wife, and each woman is to have her own husband.
3 The husband must fulfill his duty to his wife, and likewise also the wife to her husband.
4 The wife does not have authority over her own body, but the husband does; and likewise also the husband does not have authority over his own body, but the wife does.
5 Stop depriving one another, except by agreement for a time, so that you may devote yourselves to prayer, and come together again so that Satan will not tempt you because of your lack of self-control.
According to Paul, people who want to satisfy their sexual desires should do so within the marraige relationship. Each man is to have his own wife and each woman is to have her own husband. They can take a break in order to devote themselves to prayer, but then they should come back together again, just the 2 of them.
Flee Fornication! 1 Cor 6:15-18
15 Know ye not that your bodies are the members of Christ? shall I then take the members of Christ, and make them the members of an harlot? God forbid.
16 What? know ye not that he which is joined to an harlot is one body? for two, saith he, shall be one flesh.
17 But he that is joined unto the Lord is one spirit.
18 Flee fornication. Every sin that a man doeth is without the body; but he that commiteth fornication sinneth against his own body.
In verse 18, everyone is told to "flee fornication". Run, don't walk to the nearest exit when the temptation to fornicate comes around. This applies both to Christians and to non-Christians. We are urged to flee, not resist, not play around with, not to find reasons for and excuses to engage in fornication. Flee!
Pauls says that fornication is a sin against one's own body. Remember that according to the Biblical definition of fornication, anyone who sells themselves for a price, even the price of zero is a harlot. Fornication defiles the body. It is dirty. God has allowed STD's to exist in order to remind us of that fact.
Glorify God In Your Body
For a Christian the bottom line is this: "glorify God in your body" 1 Cor 6:20. Adultery and fornication do not glorify God. Instead they are a reproach to his name. For Christians it is inconsistent to be united with Christ in spirit, but then to be united with a harlot in flesh. Uniting with a harlot breaks spiritual fellowship with Christ. Again, we cannot lose our salvation but our fellowship can be impaired by indulging the flesh.
Christians should see their spiritual intimacy with Christ as being vastly superior to any physical intimacy they might have with a harlot. "But he that is joined to the Lord is one spirit". Just as a man and wife "become one flesh", those who are Christ's "become one spirit" with him. It's not a good bargain to trade in spiritual oneness with Christ for a harlot. It is much more excellent to be joined to Christ.
Related article: Why Did God Bless Men Who Had More Than One Wife?
What the Bible says about polygamy.