The Truth About Adultery

The Sermon on the Mount  •  Sermon  •  Submitted   •  Presented
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Thomas Costain’s history, ‘The Three Edwards’, describes the life of Raynald III, a fourteenth-century duke in what is now Belgium. Grossly overweight, Raynald was commonly called by his Latin nickname, Crassus, which means "fat." After a violent quarrel, Raynald’s younger brother, Edward, led a successful revolt against him. Edward captured Raynald but did not kill him. Instead, he built a room around Raynald in the castle and promised him he could regain his title and property as soon as he was able to leave the room. The problem was Raynald was so big he couldn’t fit through the door. To regain his freedom, he needed to lose weight. But Edward knew his older brother, and each day he sent a variety of delicious foods. Everyday he wheeled before Raynald on a cart, the tastiest foods. But instead of dieting his way out of prison, Raynald grew fatter from the food. When Duke Edward was accused of cruelty, he had a ready answer: "My brother is not a prisoner. He may leave when he so wills." Raynald stayed in that room for ten years and wasn’t released until after Edward died in battle. By then his health was so ruined he died within a year, a prisoner of his own appetite.
There are many of us who are like Raynald, trapped by our own sinful desires. We wish we didn’t have these desires but often the delicious temptations that are wheeled before us are too hard for our flesh to resist.

Meaninglessness does not come from being weary of pain. Meaninglessness comes from being weary of pleasure.” -G.K. Chesterton

In recent weeks we’ve transition to a portion of the Sermon on the Mount focusing on the Law. In a series of statements, Jesus uses (and will continue to expound in his sermon), “You have heard it said… but I say to you.” What Jesus is referring to is the Law of Moses being taught by the religious leaders of his day.
We’ve talked extensively about the significance of this teaching from Jesus and that Jesus said, Matthew 5:17-18 “17 “Do not think that I came to abolish the Law or the Prophets; I did not come to abolish but to fulfill. 18 “For truly I say to you, until heaven and earth pass away, not the smallest letter or stroke shall pass from the Law until all is accomplished.”
This is just a pertinent to us today as it was when Jesus taught the Sermon on the Mount 2000 years ago. There was never a point when God’s law was dissolved or nullified by the Lord Jesus Christ - quite the contrary. In fact, the Law was amplified by Jesus. However, in attempting to keep the law so precisely, the Scribes and Pharisees lost the meaning of the Law. The Law became a burden instead of a means to draw people closer to God.
“The Pharisees were so scrupulous in their keeping of the law that they would even tithe from the small spices obtained from their herb gardens (Matthew 23:23). The heart of this devotion to God is shown by modern-day Orthodox Jews. In early 1992, tenants let three apartments in an Orthodox neighborhood in Israel burn to the ground while they asked a rabbi whether a telephone call to the fire department on the Sabbath violated Jewish law. Observant Jews are forbidden to use the phone on the Sabbath, because doing so would break an electrical current, which is considered a form of work. In the half-hour it took the rabbi to decide “yes,” the fire spread to two neighboring apartments.” (David Guzik, Enduring Word).
The first way we observed this was through the idea of murder, the sixth commandment. Jesus said that the heart of the law goes beyond the act of killing, but extends to heart. Murder begins in the heart with anger. What Jesus is saying is that righteousness is expressed in our relationships with others, not just in our religious faithfulness to God.
There is no greater relationship as an image in our relationship to God than the marital relationship and that is where Jesus takes us today in his sermon:
Matthew 5:27–30 LSB
27 “You have heard that it was said, ‘YOU SHALL NOT COMMIT ADULTERY’; 28 but I say to you that everyone who looks at a woman to lust for her has already committed adultery with her in his heart. 29 “But if your right eye makes you stumble, tear it out and throw it from you; for it is better for you to lose one of the parts of your body, than for your whole body to be thrown into hell. 30 “And if your right hand makes you stumble, cut it off and throw it from you; for it is better for you to lose one of the parts of your body, than for your whole body to go into hell.
(This Outline is from John MacArthur’s Commentary on Matthew)

The Deed

The word adultery is etymologically related to the word adulterate, which means “to render something poorer in quality by adding another substance.” Infidelity is the adulteration of marriage by the addition of a third person. Adultery is sexual activity between a married person and anyone outside of the marital relationship. (
From the very start of creation, the emotional, spiritual, and physical relationship between a husband and wife were among the most sacred of relationships in the Bible, next to God. Even the relationship between a child and parents is transformed because of the marital union between a man and woman.
Genesis 2:24 LSB
24 Therefore a man shall leave his father and his mother, and cleave to his wife; and they shall become one flesh.
It should be no surprise that the marriage vows and relationship are among the most attacked by the enemy with a barrage of perversions. Marriage is used in the Bible as an image of the relationship between Israel and God, and the Church with Christ. More today than in any other time in history, the marital relationship, the sacredness of physical union, and now the divine creation of sexuality is under the relentless gauntlet of Satan’s armies. It is no wonder that Jesus issues such a high standard to believers regarding marriage and sex. So when Jesus addresses the issue of adultery, he gets into heart of the matter rather than addressing the physical act alone.
Today, sex is propagated and used to sell anything. It is pandered and exploited and made commonplace for self-fulfillment. We are taught that it is for our own selfish pleasures and lusts. Anything other than the sacred nature of what God created it for. In the Church, we turned a blind eye to issues of faithfulness in marriage, adultery, and sin. Now we have drag queens teaching children, priests who are perverts, and we are ordaining homosexuals.
Despite the Bible’s strict standards for pastors and church leaders, 1 in 5 youth pastors and 1 in 7 senior pastors report they use porn on a regular basis and currently. That’s more than 50,000 church leaders in the United States. (
Marriage and sex are so fundamental to society that it can be predicted when a society will fall based on its view of the topic. Historian J.D. Unwin studied eighteen civilizations in an effort to best determine which facts accounted for their disintegration and his conclusion was "Every society has one of two choices, either sexual promiscuity and decline, or sexual restraint and growth." (Denn Guptill, Sermon Central).
Matthew 6:22 LSB
22 “The eye is the lamp of the body; so then if your eye is clear, your whole body will be full of light.
Satan knows that and he knows how men are so easily tempted by images. It is estimated that pornography is a $10-$15 billion industry in the United States and $93 billion world-wide ( There are over 28,000 users watch porn every second on the internet and 88% of the scenes in porn films contain acts of physical aggression. 79% of those who watch porn are using marijuana and 50% will use other illicit drugs. ( Truly there are crucial issues in the sexual integrity of men and women. If Christians are the salt and the light of the world, then Jesus expects us to honor the most sacred of societal relationships ordained for mankind and that is the marital union.
Jesus goes from the sanctity of life to the sanctity of marriage. Both commandments were punishable by death according to the Law (cf. Leviticus 20:10). This shows just how urgent and consequential the issue is for God. Not only was it a prevalent issue in the Old Testament, but it continued to be reiterated in the New Testament.
Proverbs 6:32 LSB
32 The one who commits adultery with a woman is lacking a heart of wisdom; He who would destroy his soul does it.
Hebrews 13:4 LSB
4 Marriage is to be held in honor among all, and the marriage bed is to be undefiled, for the sexually immoral and adulterers God will judge.
1 Corinthians 6:18 LSB
18 Flee sexual immorality. Every other sin that a man commits is outside the body, but the sexually immoral man sins against his own body.

The Desire

So Jesus tells us that, like murder, adultery does not begin with the act, but it is a condition of the heart.
Matthew 5:28 LSB
28 but I say to you that everyone who looks at a woman to lust for her has already committed adultery with her in his heart.
It is here in the heart that we must guard ourselves against the enemy of our soul. This is the root of our sin. Society says the solution is to forgo restraint. We can hand out all the condoms in school, assign new pronouns, and pervert the image of God, but we will never address the issue at hand. It will ultimately be to our demise unless we as a society repent and change.
Jeremiah 17:9 LSB
9 “The heart is more deceitful than all else And is desperately sick; Who can know it?
The true issue is that we lust for something God has not intended to give us. We desire the forbidden fruit. Like Eve, we look at the fruit and perceive that it is good, ignoring God’s commands and determining for ourselves what is right and wrong. The dictionary definition of lust is "1) intense or unrestrained sexual craving, or 2) an overwhelming desire or craving." If we cannot control the sin of lust in the most fundamental of relationships, then we we will control the flesh in any other matter.
The Bible speaks of lust in several ways. Exodus 20:14, 17 (NLT), "Do not commit adultery. . . Do not covet your neighbor’s house. Do not covet your neighbor’s wife, male or female servant, ox or donkey, or anything else your neighbor owns," or Matthew 5:28, "But I say, anyone who even looks at a woman with lust in his eye has already committed adultery with her in his heart." (
Job 31:11–12 LSB
11 “For that would be lewdness; Moreover, it would be an iniquity punishable by judges. 12 “For it would be fire that consumes to Abaddon, And would uproot all my produce.
At the heart of lust is desiring to please ourselves and it often leads to other sinful actions in an attempt to fill desire in our heart. People will say, “Well I can look, but not touch.” or “I have the desire, but I’m not acting on that desire.” Jesus says in our passage that is folly. If you have a sinful desire you must deal with it with God.
The battleground for our souls is in our minds, in our thoughts. It is strongholds, arguments, and thoughts that exalt themselves against the knowledge of God. This is really the heart of the matter that Jesus was getting to in his sermon. Our sexual fidelity is among the core issues of our lives. It is also a reflection of our love and devotion to God because it is rooted in a singularly devoted heart.
Deuteronomy 10:12 LSB
12 “So now, Israel, what does Yahweh your God ask from you, but to fear Yahweh your God, to walk in all His ways and love Him, and to serve Yahweh your God with all your heart and with all your soul,
Deuteronomy 11:1 LSB
1 “You shall therefore love Yahweh your God, and keep His charge, His statutes, His judgments, and His commandments all your days.
God says to us that we learn to love Him, whom we cannot see, by learning to love those around us whom we can see and the first and most prominent person in that list of relationships is your spouse. With that our attitude toward sin and our devotion to God is that of a war that must be won

The Deliverance

Matthew 5:29–30 LSB
29 “But if your right eye makes you stumble, tear it out and throw it from you; for it is better for you to lose one of the parts of your body, than for your whole body to be thrown into hell. 30 “And if your right hand makes you stumble, cut it off and throw it from you; for it is better for you to lose one of the parts of your body, than for your whole body to go into hell.
Obviously, Jesus is using a figure of speech to drive the point home on the urgency of the matter. Jesus is using repugnant images to show us just how repugnant sin is to him. Never does Jesus minimize the serious of sin, but that it should be addressed as such. It is far better to give up something that is important to us rather than let it destroy us.
The addict can never entertain the drug, the alcoholic can never be around the drink. The temptation is too strong. I know guys who cannot go to a beach or a be on social media because the temptation is too great. Stop entertaining sin. Does it hurt to look? It most certainly does! Remove the object of your lust as far from your life as possible and have those closest to you hold you accountable. The first person on that list must be your wife.
Be it pornography, another man or woman, movies, the internet, we should live our lives as if we have no eyes. Deal with sin head-on and deal with it openly.
Matthew, Volumes 1 & 2 The Heart Issue

The cause of marital discontentment is less “my spouse’s flaws” than it is a hard-hearted response to those flaws.

Last, champion your spouse. Culture says, “Get the best partner you can.” Every man deserves a ‘trophy wife.’ Every woman deserves the perfect husband in body, soul, and mind. What this breeds is discontentment. Discontentment drives out the love and respect for your wife or husband. Celebrate the marriage God has given to you. Discontentment is prideful. Contentment loves your spouse in all their imperfections and the scourge of the roving eye.
1 Corinthians 7:3 LSB
3 The husband must fulfill his duty to his wife, and likewise also the wife to her husband.


The desire of God is for us to enjoy His blessings He pours out into our lives every day. Sin blinds us to blessings of God. Instead we are focusing on the lusts of our hearts.
Philippians 4:8 LSB
8 Finally, brothers, whatever is true, whatever is dignified, whatever is right, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence and if anything worthy of praise, consider these things.
2 Corinthians 10:5 LSB
5 as we tear down speculations and every lofty thing raised up against the knowledge of God, and take every thought captive to the obedience of Christ,
1 Corinthians 6:18 LSB
18 Flee sexual immorality. Every other sin that a man commits is outside the body, but the sexually immoral man sins against his own body.
1 Timothy 6:11 LSB
11 But you, O man of God, flee from these things, and pursue righteousness, godliness, faith, love, perseverance, gentleness.
James 4:7 LSB
7 Be subject therefore to God. Resist the devil and he will flee from you.
Jesus’s desire is for us to live under the immense blessings of God. Will you reject sin for the blessings of God by coming to Jesus today?
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