“Adultery & the Heart”

“Adultery & the Heart”

Matthew 5:27-30

Matthew 5:27-32 is a great example for why expository preaching is something that is needed and good for the Church.  I say this because in all honesty, preaching on anything related to sex, or that addresses divorce, are probably the most uncomfortable subjects for me to preach on.  The only other subject that is as uncomfortable for me to address as a pastor is the subject of money.  I also recognize that sex and divorce have brought so much pain and confusion; there are lifelong impacts from lust in the human heart and trauma from divorce.  I want you to know that I am approaching what Jesus says in these verses with as much care and sensitivity that I am able.

Before we dive into what Jesus says about adultery (this week) and divorce (next week), I want to assure you that if you will commit to prayerfully listen to both this sermon and next week’s sermon, I believe you will find help in time of need and healing in the midst of your pain.  I have said this before and I want to especially stress it before I begin: The Bible is not God’s method to wreck or kill your joy, but to maximize it.

So… let’s dive into our passage today.  Remember what Jesus said in Matthew 5:20, “Unless your righteousness exceeds that of the scribes and Pharisees, you will never enter the kingdom of heaven.”  Jesus then shows us how the Law in the Old Testament addresses issues of the heart and was never intended to serve as a check list to see how righteous you are.  Just as Jesus shows us that the sixth commandment concerning murder addresses what is really in our hearts, so he shows us that the commandment about adultery is addressing more than marital fidelity.  Jesus said: “You have heard that it was said, ‘You shall not commit adultery.’ But I say to you that everyone who looks at a woman with lustful intent has already committed adultery with her in his heart” (v. 27-28). 

Someone may say in response to these verses: “Isn’t that a bit harsh for Jesus to say?”  My answer to that is, “No.”  I believe that what Jesus is doing is three things: First, he is treating sex as something that is sacred instead of common.  Second, Jesus is treating sex as a gift instead, as he is the giver. Third, he is treating sexuality as a part of us and not something that identifies us. 

Sex is Sacred

I struggled with the wording of my first point; I wasn’t sure if the wording of my first point should have been, “People are Sacred” for reasons I will explain shortly.  Here again Jesus said something that most likely did more to anger the scribes and Pharisees, for they thought that so long as they did not have any sexual contact with any woman except with their own wives that they remained perfectly obedient to the seventh commandment: “You shall not commit adultery” (Exod. 20:14).  It did not matter what they thought about another female so long as they did not sleep around. 

When we read Genesis 1, we read that God created the day to separate the darkness and that there was morning and night on the first day.  Then we are told that God separated heaven and the earth on the second day.  And on the third day, God separated the land from the sea.  After God created the plants, trees, vegetation, and the rest of the creatures on the fourth and fifth days, he created both male and female on the sixth day as the climax of his creation: “So God created man in his own image, in the image of God he created him; male and female he created them” (Gen. 1:27).   Do not miss the significance of the complementarian nature of creation: morning complements evening, the earth complements the heavens, and the land complements the sea.  There is order and unity in a diverse creation that includes male and female who are the same but also uniquely different. 

We are told that what sets the man and the woman apart from the rest of creation is their role to do two things: To create and fill the earth with people like themselves and to manage creation.  Here is what Genesis 1:28 states: “And God said to them, ‘Be fruitful and multiply and fill the earth and subdue it, and have dominion over the fish of the sea and over the birds of the heavens and over every living thing that moves on the earth’” (Genesis 1:28).  However, in Genesis 2, we are given a more descriptive explanation of how God created Eve for Adam from his rib; it is in Genesis 2:24-25 that we are told of the sacredness of sex and marriage: “Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh. And the man and his wife were both naked and were not ashamed” (Genesis 2:24–25).

What the scribes and Pharisees did get right theologically was that marriage was a covenantal relationship between a man and a woman instituted by God.  However, their understanding of faithfulness and how they treated their wives was based on what could be seen and had little to do with what was in their hearts.  We know this because of the prevailing belief in Jesus’ day that a man could divorce his wife for just about any reason (see Matt. 19:3-9) as long as he did not have sex with another woman while married.  The punishment for any sexual sin outside of marriage according to the Mosaic Law was severe (see Lev. 20:10-21), and the scribes and Pharisees where quick to carry out such punishments on others (see John 7:53-8:11).  They thought they were innocent of adultery, but to lust after another is to expose a much deeper problem than what people can see. 

What Jesus shows us in his sermon is brilliant, and what he shows us is to lust after a person who is not your spouse is to devalue that person as less than human.  To lust after a person is to reduce the act of sex down to something not sacred but common and the person you are lusting after as nothing more than an object for your own pleasure.  Not only does lusting after someone other than your spouse devalue that person, but if you are married, it also devalues your spouse. 

We live in a culture that treats sex as common and something to experiment with, and experience with few barriers, if any.  So long as you are careful not to get pregnant or spread an STD, then our culture says that we ought to have at it for our own pleasure so long as those involved are consenting.  Yet, Jesus uses very strong language for anyone who treats sex in that way: “What comes out of a person is what defiles him. For from within, out of the heart of man, come evil thoughts, sexual immorality, theft, murder, adultery, coveting, wickedness, deceit, sensuality, envy, slander, pride, foolishness. All these evil things come from within, and they defile a person” (Mark 7:20–23).  Jesus says that such acts defile a person and that they are evil.

According to Jesus, sex is a gift that God has given to be treated as sacred and to be enjoyed only within the bounds of the marriage covenant.  A covenant is something much deeper than a friendship, compatibility, romance, or even love.  A covenant includes all those things, but it is more because it involves a promise that is binding.  It cannot be consumeristic because it requires the persons entering a covenant to adjust to the other because of the importance of the relationship.  Tim Keller described a covenant in this way: “A covenant relationship says, ‘I will adjust to you, because I’ve made a promise, and the relationship is more important than my needs. My needs are less important in the sustenance of the relationship.”[1]  Yet any time we lust after another person, engage in sex outside of marriage, or break your promise to your spouse by committing adultery, you pervert sex and make it into something to be consumed instead of something to be shared.    

The Gift is NOT the Giver

Jesus, and all of Holy Scripture, treats sex as a gift from God.  Jesus shows us in his statement about adultery that lusting for another person who does not belong to you reveals something much more hideous in us.  That hideous thing is the propensity we all have to confuse the gift with the giver.  We make what is good and treat it as something ultimate, something greater than what it is.  This is what our human beings tend to do with sex.  When we make good things into ultimate things, those things become something we feel we cannot live without.  Our identity becomes infused in that thing we make ultimate in our lives.  This is what our culture has done with sexuality; any sexual orientation a person feels drawn to is the place that person is encouraged to find his/her identity in.  This is also what the evangelical church has done with sex by encouraging people to find their identity through heterosexual relationships while ignoring the fact that some of the biggest names in the Bible are people who were single and never married; such as Jesus, Jeremiah, Elijah, Daniel, John the Baptist, and the apostle Paul.    

Within the marriage covenant, we are told in Genesis 2 that both the husband and the wife become one flesh and are united together as no other can be united.  Within the union of marriage, we learn of Adam and Eve what every married couple is meant to experience: “And the man and his wife were both naked and were not ashamed” (Gen. 2:25).  What we learn from the Bible is that sex is a gift from God to be enjoyed and shared only between a man and a woman in the context of marriage where they are meant to enjoy a loyalty between each other that is exclusive, lifelong, and physical.  Married couples are encouraged to enjoy sex (Prov. 5:18-19), to not withhold it from each other (1 Cor. 7:1-5), to honor each other (Eph. 5:22-33), and to keep it sacred (Heb. 13:4).  However, it is only a good gift from God and was never given by God so that we can make a god out of it.  Daniel Doriani, a theologian, said of God’s design of sex,

By its very nature, physical love is a life-uniting act.  God intended it to be a sign and a seal of the union of two lives. “Casual sex” is a misnomer.  Sex is no mere bodily function.  Our bodies are us…. “When two bodies are united, two persons are united.  Nobody can go to bed with someone and leave his soul parked outside.  The soul is in the act.”

Therefore, the trouble with extramarital sex is that it is “a life-uniting act committed without life-uniting intent.”  It is not just adultery; it is a thieving lie.  Intimacy is a sign and a seal of the union of two lives.  But outside of marriage, the act and the intent clash.  Intimacy of body and intimacy of soul go together.  That is why adultery—as well as other sexual relations outside of marriage—is wrong.[2] 

In fact, sex in any form outside of the context of marriage is sin.  This is why we are warned in the Bible:

Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived: neither the sexually immoral, nor idolaters, nor adulterers, nor men who practice homosexuality, nor thieves, nor the greedy, nor drunkards, nor revilers, nor swindlers will inherit the kingdom of God…. Flee from sexual immorality. Every other sin a person commits is outside the body, but the sexually immoral person sins against his own body. (1 Corinthians 6:9-10, 18)

And, when it comes to eternal life in the presence of God on a new and resurrected earth where the curse of sin will no long have a place, we read these sober words:

And he who was seated on the throne said, “Behold, I am making all things new…. It is done! I am the Alpha and the Omega, the beginning and the end. To the thirsty I will give from the spring of the water of life without payment. The one who conquers will have this heritage, and I will be his God and he will be my son. But as for the cowardly, the faithless, the detestable, as for murderers, the sexually immoral, sorcerers, idolaters, and all liars, their portion will be in the lake that burns with fire and sulfur, which is the second death. (Revelation 21:5–8)


This is why Jesus used such strong language in his sermon regarding adultery and lust.  Sex is sacred and it is a gift to be experienced, enjoyed, and celebrated within the context of a holy covenant called marriage.  To pervert sex, to treat it as common, to abuse it, or to idolize it is to put yourself in great peril under the wrath of a holy God.  So serious is sexual sin that Jesus tells us to get radical with addressing it: “If your right eye causes you to sin, tear it out and throw it away.  For it is better that you lose one of your members than that your whole body be thrown into hell.  And if your right hand causes you to sin, cut it off and throw it away.  For it is better that you lose your members than that your whole body go into hell” (Matt. 5:29-30).

Do not let the sequence of the heart, then the eyes, then the hands go unnoticed here.  From where does adultery or any other sexual sin spring out from?  It comes from the heart.  From the heart; you can lust from your heart without your eyes or your hands, but the lust of your heart will find its way to your eyes and then eventually your hands.  Origen, an early church father, took Jesus literally by rolling over sharp thorns while naked.  When that didn’t help address his struggle with lust, he castrated himself.  Sometime after he castrated himself, he discovered that not even that could fix his problem of lust in his heart and later admitted that he may have misinterpreted what Jesus meant in Matthew 5:29-30. 

So, what is it that Jesus is really saying here?  First, he is saying that what is in the heart will find its way to the eyes and then eventually result in you taking what is not yours to take.  Jesus is saying that the stakes are so high regarding sexual sin, or any sin for that matter, that we must take radical steps in addressing our sin and the place to begin is the heart.  The good news is that if you are truly a Christian, in the sense that you arrived before Jesus as one who is poor in spirit (the recognition that you need a righteousness only Jesus can provide), as one who mourns of your sin, and one who is meek (a willingness to submit to the will of God), God is already at work in your heart. 

If you are a Christian, God has given you new appetites and the way that you know that he has given you new appetites is that the lust in your heart really bothers you.  The Bible calls this change in your appetites a “circumcision of the heart” (see Deut. 30:6; Ezek. 26:24-27; Jer. 31:31-34), and this is what it means to be born again according to Jesus (John 3:3-16).  The evidence that this has happened in you is that you now, “hunger and thirst for righteousness” that can only be satisfied through Jesus.  The point Jesus is making is that the sin is so dangerous that it is better to get rid of whatever it is that makes sinning easier for you.  If it is your smart phone, get a flip phone.  If it is whatever services you subscribe to for your TV, get rid of the service or get rid of the TV.  If it is the gym, end your membership.  Whatever it is, get radical concerning your sin and get rid of the thing that makes sinning easier.  For Job, one of the ways he fought against the lust in his heart is that he guarded what he looked at: “I have made a covenant with my eyes; how then could I gaze at a virgin” (Job. 31:1).

Tim Keller says in this book, Counterfeit Idols that the best way to destroy the idols in your life is to replace them with something greater.  In our case, that something is a someone, and that someone is Jesus.  What I have found in my life is that the closer I draw to Jesus, the stronger my resolve is to live for him and fight against my sin.  I will tell you though, there will be some sins in your life that you will gain victory over and there will other sins in your life that it will be an ongoing battle.  The point of Jesus’ Sermon on the Mount is that you need a righteousness you cannot generate on your own; you need Jesus!  He is the only one who can satisfy your heart and he is the only one where your identity can be rooted that will not lead to spiritual death. 

Permit me to give you some steps that I believe you will find helpful as you battle the lust for sin in your own heart:

  • Realize the seriousness of sin and where it leads people, and where it leads people is hell.
  • Address the real cause of your sin, which is your heart.  The only remedy for your heart problem is the gospel of Jesus Christ.
  • See people as individuals created in the image of God with value and worth.  Any sin that involves another person such as lust, must involve you making that person an object to be used instead of a person to be honored.
  • Understand that your real identity is found in the One whose image you reflect, namely God.
  • Recognize what it is that makes sinning easy for you and act decisively and immediately to remove it from your life (e.g. a smart phone, a place, a person, etc.).
  • Treasure Jesus above all things for he is the only one who can satisfy the hunger of your heart and soul. 
  • Memorize 1 John 1:8-9, “If we say we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.” (1 John 1:8–9)

Discussion Questions:

  1. Why do we commit adultery in our hearts by lusting after another person? 
  • How much damage can committing adultery in the heart create?
  • The heart is an idol factory that often makes good things into ultimate things.  How have we as a society made sex into an ultimate thing?
  • Read Ephesians 5:22-33. In light of what the apostle Paul says of marriage, why is sexual sin (sexual immorality) so dangerous and why does God threaten hell to those guilty of it?
  • What did Jesus mean in Matthew 5:29-30 by tearing out your right eye and cutting off your right hand? 
  • Romans 8:13 states, “For if you live according to the flesh you will die, but if by the Spirit you put to death the deeds of the body, you will live.”  In light of what Jesus said in Matthew 5:29-30 and what Paul wrote in Romans 8:13, what are some practical ways to “put to death the deeds of the body”? 
  • Read 1 Thessalonians 4:3-8.  What is it that God is calling you to and by what power are you able to get there (hint: notice what Paul says in verse 8)?
  • Read 1 John 1:8-9.  In light of this passage, do you think God wants you to be paralyzed by shame over past sins?  How does one move towards holiness in the midst of past and present failures?

[1] Keller, T. J. (2013). The Timothy Keller Sermon Archive, 2012-2013. Redeemer Presbyterian Church.

[2] Daniel M. Doriani, Reformed Expository Commentary: Matthew Vol. 1 (Phillipsburg, NJ: P&R Publishing; 2008), p. 155.