An Undivided Heart

Matthew 5:27-37

Immanuel – 1/21/24

The Sermon on the Mount is the single longest teaching of Jesus’ ever recorded. Its importance cannot be understated; and without a doubt, it is the greatest sermon of all time. And this greatest of all sermons is entirely about the kingdom of God: What it is, how it functions, and how we are to live within it.

Since we all – followers of Jesus Christ – are members of the kingdom of God, then how great is this privilege that we get to freely feast upon the Sermon on the Mount!

As we continue our journey through the Sermon on the Mount, let’s look back at a passage that is critically important for our understanding today.

Read vs 17-20

Christ is not abolishing the Old Testament Law nor invalidating it; He is fulfilling it. And when the Old Testament Law (or Mosaic Law) is fulfilled, another form of law stands in its place. That is exactly what Jesus is showing us through the Sermon on the Mount, a new form of law: the law of the kingdom of God. Though I have said this before, remember, the law of the kingdom of God works differently than the Mosaic Law.

From Matthew 5:21 to the end of the chapter, Jesus is proving to us just how differently these two laws function.

Among sinful men, the only righteousness the Mosaic Law is able to reveal is a righteousness like the Pharisees: a self-justifying and hypocritical righteousness. Conversely, the law of the kingdom of God actually produces genuine, authentic righteousness: a righteousness that exceeds the Pharisees. Like verse 48 says, the law of the kingdom of God produces such a complete righteousness that we may truly be perfect as our Heavenly Father is perfect.

It would be easy for me to talk about how to combat lust, or how to stay married, or how to be true to our word; but I don’t believe that’s what Jesus is after in this passage.

Purpose

What is the righteousness that Jesus is directing His disciples towards?

Read vs 27-28

Lust and Adultery

“You have heard it said, ‘You shall not commit adultery.’” Every single Jew sitting around Jesus on the mountain would have know exactly where they have “heard it said.” That is the 7th of the 10 commandments:

“You shall not commit adultery.” -Exodus 20:14

Then Jesus says, “But I say to you.” Eric Moore did a tremendous job bringing the Word last week; and he was exactly right to say that Jesus was elevating Himself to the position of Yahweh with a statement like this. “Yahweh has said, but I say to you. Yahweh has said ‘Do not commit adultery’, and I say with the same authority, ‘Do not lust.’”

Again, Jesus is not invalidating the former law. He is setting up a contrast. He is going to contrast outward behaviors with inward desires of the heart. Thus, Jesus is taking the Mosaic Law to its ultimate end, where it forces us to see that we fall short, where it compels us to seek God. Ultimately, Jesus of Nazareth is drawing every person to see the fulfillment of righteousness in Him, God the Son.

Now, to really feel the gravity of contrast, we need a working understanding of lust. You can lust after anything; which essentially is to covet that thing. “You shall not covet” is the 10th commandment. To lust, or to covet, is to want something for yourself that you do not own. But lusting after a woman, as Jesus refers to in verse 28, is to want a woman sexually.

I want that to be crystal clear, because Jesus is not talking about looking at another person and finding them attractive. There is nothing sinful in that. It is when you have an attraction and then you begin to entertain sexual fantasies with that person. That is lust.

Lust is the sinful desire; adultery is the wicked action that follows. Adultery is what you do with your body, lust is what you do in the heart. Lust betrays the sick and sinful condition of the heart.

And how devastating are Christ’s words! In the Mosaic Law, the consequence for adultery was death; now Jesus equates lust with adultery!

Every lustful look, every sexual fantasy entertained: adultery. For men – who are stimulated by visual beauty and whose hearts are sinful – this is terrible news. Thus, according to Christ’s words, I am solemnly confident in saying that every married man in this room is an adulterer. I am an adulterer. And to possess such an adulterous heart is to earn a death sentence.

Some of you may have felt a little relief here because it sounds like Jesus might only be speaking to married men. You have to be married to commit adultery. And in this context, is Jesus not speaking to men who look lustfully at women? But if you think this is just for married men you miss Jesus’ point and you think like a Pharisee.

Jesus is aiming at the heart, the heart of every person. Thus, any married woman that looks at a man with lust is also an adulterer – even if she lusts after an emotional connection or romantic engagement. Unmarried men and women lustfully coveting another person, you are guilty of sexual immorality.

The Pharisaic mindset would find exceptions in Jesus words and self-justify. The disciple understands that no one escapes. Everyone is desperately in need of righteousness.

Read vs 29-30

I hope you can see that Jesus is speaking hyperbolically, in exaggerated terms. Those who claim to take the Bible literally need to be careful with what they mean; for truly, Jesus is not recommending that we dismember ourselves in order to enter heaven. Those who want to turn Jesus’ words into a system of rules are really going to struggle at this point.

Rather, Jesus implores His disciples to wage war against our sinful desires. It is more valuable that you kill your sin than you keep your arms. As Paul writes,

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. -Romans 8:13

Sin and lust lead to death. Purity and self-control lead to life. Yes, it’s far greater to enter heaven one-eyed and one-armed than it is to have a whole body cast into the eternal fire. Of Romans 8:13 the Puritan, John Owen, famously said, “Be killing sin, or sin will be killing you.” So, disciples of Jesus Christ, we make it our aim to kill sin before it kills us! In the fight against lust, it is kill or be killed.

Read vs 31-32

Divorce and Adultery

Once again, Jesus harkens back to the Mosaic Law, but this time not from one of the 10 Commandments. I think it is important we read that passage in full.

When a man takes a wife and marries her, if then she finds no favor in his eyes because he has found some indecency in her, and he writes her a certificate of divorce and puts it in her hand and sends her out of his house, and she departs out of his house, and if she goes and becomes another man’s wife, and the latter man hates her and writes her a certificate of divorce and puts it in her hand and sends her out of his house, or if the latter man dies, who took her to be his wife, then her former husband, who sent her away, may not take her again to be his wife, after she has been defiled, for that is an abomination before the LORD. And you shall not bring sin upon the land that the LORD your God is giving you for an inheritance. -Deuteronomy 24:1-4

This is the only passage that mentions divorce in the entire Mosaic Law, and you will notice that it neither affirms nor condemns divorce. Rather, it deals with the fall-out from divorce. God was setting boundaries around the brokenness of divorce.

But the sinful and self-justifying heart took this passage as a license for divorce. That’s how the sinful heart works, looking for license in wickedness.

So, manufacturing license from the Mosaic Law – in Jesus’ day – a man could divorce his wife for any reason at all. Among the teachings of the Pharisees, he could divorce her for a spoiled dinner. It was then as simple as writing a certificate and reading it before a few local officials. Divorce finalized.

There was no provision for a woman to initiate divorce except through a lengthy court process.

But Jesus, completely upending the Jewish traditions of divorce, proclaimed that the only valid reason for divorce is infidelity. Understand why sexual immorality validated divorce: From the beginning, from Eden, God established marriage:

A man shall leave his father and mother and hold fast to his wife, and they shall become one flesh. -Genesis 2:24

If two become one flesh, and one of them cheats, how can you add another one flesh? It is impossible. Infidelity breaks a marriage at its very root. The certificate of divorce, which God allowed because of the people’s hardness of heart, is a sad recognition of an already destroyed marriage.

Do not receive Jesus’ words like you would receive the Mosaic Law. He does not deliver precise regulations on divorce. He is delivering principles meant to guide life and conduct. I can all the more confidently say this because in the principle of Jesus’ teaching, in 1 Corinthians 7:15, Paul makes provision for divorce if an unbeliever abandons his/her believing spouse. In accordance with this principle, I hold the conviction that abuse is grounds for divorce.

In God’s forbearance, in His infinite patience, He made a provision for divorce because of our sinful hearts. Divorce is a result of sin and stupidity. Divorce is an expression of hardhearted brokenness. Divorce was never meant to become acceptable or easy or light, not like it was in Jesus’ day, not like it is in our era of “no-fault divorce.”

Marriage is and was always created to be a union of one man and one woman for life. What God has joined together, let not man separate (Matthew 19:6).”

To further emphasize the seriousness and value of marriage, Jesus says that anyone who divorces his wife makes her commit adultery and anyone who marries a divorced woman commits adultery. This takes a little unpacking.

Jesus says that the only legitimate reason for divorce is if there has been adultery. Thus, in the eyes of God, if people get divorced for illegitimate reasons and then engage in sexual activity with another, even within the context of a second marriage, they have committed adultery.

Additionally, if a man divorces his wife for any other reason besides sexual immorality (or vice versa), he treats his wife as if she has committed adultery. Thus, he has effectively branded her as an adulteress.

I hope you can see that Jesus was laying down the highest standard for marriage in an age when marriage was regarded as cheap.

Jesus’ standard for righteousness is exceedingly high. Remember Jesus’ most recent words, “Everyone who looks at a woman with lustful intent has already committed adultery with her in his heart” (vs 28).

It is an outrageously high standard. Are these two things in conflict with one another? If God desires that marriage last a lifetime, yet everyone is an adulterer at heart, then who can hope to be righteous? What is this righteousness that exceeds that of the scribes and Pharisees? Who can be perfect as God is perfect? What kind of law is this?

Jesus’ words bring you inevitably to these questions, and yet He does not attempt to rescue them. He only continues to raise the standard with the next section.

Read vs 33-37

Oaths

There are elements of this exhortation in the 3rd commandment (You shall not take the name of the Lord your God in vain) and the 9th commandment (You shall not bear false witness). But most precisely, Moses speaks of oaths in Deuteronomy.

If you make a vow to the LORD your God, you shall not delay fulfilling it, for the LORD your God will surely require it of you, and you will be guilty of sin. But if you refrain from vowing, you will not be guilty of sin. You shall be careful to do what has passed your lips, for you have voluntarily vowed to the LORD your God what you have promised with your mouth. -Deuteronomy 23:21-23

To make a vow to the Lord is to promise something to the Lord. If you break it, you prove your guilt and sinfulness.

To swear an oath is to make a promise to a person. If you swear an oath to another person, in the name of God, you communicate that God is the guarantor of that oath. In other words, “If I fail, God will make good on it.” But who are you to say God will make good on your word? And if you break your oath, you bring disgrace upon the name of God.

Some Jews, not wanting to disgrace the name of God still desired something sacred that would add validity and solemnity to their word. So, they would swear by heaven, or by earth, or by Jerusalem, and debated over which one held greater weight. Others said no oath was valid unless it was pledged in the name of God. Still others, fearing to invoke anything sacred, took oaths upon their own heads; meaning they would lose their head if they broke their promise.

But Jesus overtly rejects all such hair-splitting moralistic debating. He even rejects the motivations that would lead a person to pledge oaths on things they have no control over.

Again, remember that the law of the kingdom of heaven does not work like the laws of men. Jesus is not delivering literal regulations. We do not need to refuse to take oaths in the court of law; for though we are citizens of the kingdom of God, we live for a time within the kingdoms of men. And though in a perfect world, oaths are not needed, we do not presently live in a perfect world.

Even Christ submitted Himself to the oaths of man.

The high priest said to [Jesus], “I adjure you by the living God, tell us if you are the Christ, the Son of God.” Jesus said to him, “You have said so. But I tell you, from now on you will see the Son of Man seated at the right hand of Power and coming on the clouds of heaven.” Then the high priest tore his robes and said, “He has uttered blasphemy. What further witnesses do we need? You have now heard His blasphemy.

-Matthew 26:63-66

Jesus revealed His divine nature under oath. The religious leaders understood it; and in their unbelief they decried the revelation as blasphemy. Within hours Christ was on the cross. The King of heaven and earth, condemned by the kingdoms of men, and that condemnation came when He spoke truth under oath.

Again, we see that the kingdom of heaven functions on an entirely different level than the kingdom of earth. Christ’s is a kingdom of righteousness, where its citizens love the truth and live not by lies. And if its citizens speak the truth, then there is absolutely no need to make oaths or vows, nothing needed to guarantee your word. Like Jesus said, “Let what you say be simply ‘Yes’ or ‘No.’

James echoes the words of his half-brother.

But above all, my brothers, do not swear, either by heaven or by earth or by any other oath, but let your “yes” be yes and your “no” be no, so that you may not fall under condemnation. -James 5:12

So, do you see what Jesus has done? Not only has He upended the moralistic practices of the day, but He has commanded that His people embody truth. “If you say it, do it. If you make a promise, fulfill it. If you cannot, do not give your word. Be reliable. Be committed. Be a person of integrity. Be true. Do it because you follow the One who is the source of all truth. Do it because you represent His kingdom.

And how much more so, when before God we stand at that wedding altar and make a vow, to love and to cherish until death do you part. This vow is broken through infidelity. You disgrace your vow, your bride, and your God vow when – in your heart – you burn with lust for another.

Three times we read Jesus say, “You have heard that it was said, but I say to you.” As I said earlier, Jesus is drawing a contrast, contrasting outward behaviors with inward desires of the heart. He is moving people away from their self-justifying, legalistic laws and into His new law: the law of the kingdom of heaven.

Now let me be absolutely clear on how Jesus does in each one of these three sections: lust, divorce, and oaths.

First, Jesus is pointing at our desires rather than our behaviors. Jesus is not after behavior modification. He is after heart transformation.

Second, no amount of rule following or avoidance of sin can produce the righteousness that God demands.

R.T. France writes: “It is only the most sanguine of disciples (or those with little self-awareness) who can comfortably attempt simply to put into practice this teaching, with its culmination in the requirement that our lives should be “perfect as your heavenly Father is perfect.”1

Third, Jesus is moving His followers away from rule following and into open-ended pursuit. He is leading towards something that is beyond our grasp, something that He can only give, something that is only available through relationship with Him. For when we realize that we are at the end of ourselves, we see that we must repent and trust in Him.

Fourth, Jesus satisfies those who hunger and thirst for righteousness with His own righteousness.

“Blessed are those who hunger and thirst for righteousness, for they shall be satisfied.” -Matthew 5:6

For our sake He made Him to be sin who knew no sin, so that in Him we might become the righteousness of God. -2 Corinthians 5:21

Praise be to God who sent us His Son to live among us, to show us perfect righteousness. And then that perfectly righteous One submitted Himself to our consequence for unrighteousness. He bore the penalty of the law that we lawbreakers had earned. His perfectly innocent hands impaled with our nails, His pure heart pierced by our wickedness, His holy body swallowed in the death we deserved.

And then it was finished. All was finished but for one final act. For in three days’ time the Light of the World burst from that Judean tomb and death was swallowed up in victory! O death where is your victory? O death where is your sting? (1 Corinthians 15:55)

The Risen King, Jesus Christ, lives. Jesus took up our death and our debt has been paid in His blood. Now the Risen King beckons us to take up His life where He will clothe us in His righteousness. Christ does this, through the Holy Spirit, by ripping out our stone-cold hard hearts and gives us an undivided heart.

He has given us a righteousness that exceeds that of the scribes and Pharisees, a righteousness that transcends any laws of earth. This is the law of the kingdom of heaven, where sinners are made righteous by faith in the life, death, resurrection, and ascension of Jesus Christ, Son of God.

Every lust is forgiven. Your every falsehood, pardoned. Jesus Christ is your righteousness. Believe in Him and you shall be perfect, as your heavenly Father is perfect. This is the law of the kingdom of heaven. It is a law that does not work on the basis of regulation and achievement, but on the basis of love and grace.

“Blessed are those who hunger and thirst for righteousness, for they shall be satisfied.”

“Blessed are the pure in heart, for they shall see God.”

“Blessed are the poor in spirit, for theirs is the kingdom of heaven.”

1France, R.T. (2007). The Gospel of Matthew. Pg 195. Grand Rapids, MI: William B. Erdmans Publishing Company.