Introduction

Connie and I live 5 minutes away on a corner lot in a small subdivision. It takes about 40 minutes to cut the grass and what I’ve discovered is that if I regularly keep my front lawn cut it looks okay. And from afar it looks good, it looks pretty green. But don’t look too close. Oh there’s green grass there but there’s also green weeds and other stuff - you’re not sure - is that grass or something else?

As Christians we can be tempted to live our lives like that. If I keep my external behavior looking good I can appear okay or even as if I’m doing well. All the while I can be  struggling or rebelling on the inside, in my heart. One of the things we find out in the Sermon on the Mount is that Jesus is not interested in external behavior only but very much concerned with our inner life, that is, what is going on in our hearts.   

And in our text this morning our Savior is addressing His disciples concerning sexual sin and specifically sexual sins of the heart. None of us are immune to this temptation.  You may or may not struggle with this but many do. If you do not, please do not make the mistake that you could never be tempted to sin in this way. 

Sexual immorality is one of the idols of our age. Being able to sleep with whoever one pleases or to think about others however we may want. But this is not the Kingdom of God. Remember the Kingdom of God is where Christ reigns as king. 

Now fortunately Jesus not only condemns this behavior but also gives us hope of how to deal with it. Now His remedy is a radical solution but one that will help us to defeat these sins of the heart. There are many means of grace that God gives us to prevail over temptation and sin. What we find in the Sermon on the Mount is that God’s grace  comes to us as we allow the words of our Savior to speak directly to us. One of the highlights of chapter 5 has to do with the fact that Jesus says six times, But I say to you! (You have heard that it was said).

The King is speaking to us. We must hear Him this morning regarding what He has to say to us in this challenging area of life. He is the King, the One  who has the right to speak into our lives concerning all things including how we think about sex. And it is a mark of His disciples to desire to hear Him concerning every area of life - even in areas that we are struggling or being sorely tempted. 

Understand What’s Going On In Your Heart

So how do we fight against sexual sin in our hearts? One by understanding what’s going on in our hearts. Second, by understanding the seriousness of sexual sins. And third by understanding and applying vigilance in the war that daily goes on in our hearts with sin.  

Before we start it’s good to remind ourselves about a few things. One, this is not a message just for men. I know it is an area that many Christian men struggle with.  But it is also a sin that can tempt women as well. Secondly it is not a teaching specifically about pornography though the root sins that Jesus is addressing and its remedies are very applicable to those who struggle in that area. Third, this lusting after others that Jesus condemns can apply to heterosexual desires and same sex desires/lust.  Maybe you are tempted in that second area and are ashamed or embarrassed to admit it. The same remedy that Jesus gives for hetersexual lust applies to this area as well. 

And let us be clear. God created and ordained sex to be enjoyed within a covenant marriage between a man and a woman. Scripture celebrates and elevates sex as a marital blessing. Read Proverbs 5 or Song of Solomon and try not to blush because it is unabashed in its celebration of this blessing of God. However like any blessing from God our flesh and Satan will seek to pervert the goodness of God. 

Jesus is addressing sins of the heart so it’s very important to know what is going on in our hearts. Now I am going to be addressing sins of the heart that have to do with sexual sins because that’s what our text is addressing. But there are many sins of the heart and I hope that what I have to say will have application to other sins that you might battle. 

It’s vital that we understand the dynamics of what goes on in our inner life. In our mind, our thoughts, our affections and desires. So what is going on in regards to the sins Jesus is addressing?

We Want Something That Doesn’t Belong To Us:
 

So the first thing that’s going on is that we want something that doesn’t belong to us. Jesus is addressing both the seventh and the tenth commandments. The seventh commandment is do not commit adultery. The tenth is you shall not covet. When we covet we desire something that God has not given us. Something that doesn’t belong to us and which belongs to someone else. If you are coveting a woman who isn’t your wife if she’s married she belongs to her husband (and he belongs to her). If she is single she in a sense belongs to her family and to the Lord. 

Jesus addresses this coveting as lustful intent (ESV). Another translation reads cherishes lustful thoughts. It goes beyond a simple desire -  to actually committing sexual sin in one’s heart with that person. This lustful intent is allowed to continue in our hearts when we ignore that what we desire is something that God has not given us.  

This lusting and coveting includes continuous looking, not just noticing someone’s beauty but as one commentator wrote “imbibing it, meditating on it seeking to possess it”. Proverbs 6 instructs us not to desire her beauty in your heart.  It also includes the quick lustful look. Now it is not wrong to notice someone’s attractiveness but we must be aware of the “slippery slope” that James 1 describes:

But each person is tempted when he is lured and enticed by his own desire. Then desire when it has conceived gives birth to sin, and sin when it is fully grown brings forth death. James 1:14-15

Noticing someone’s attractiveness must stop there. We must not be led down the path of temptation or take the invitation of our sinful desires. We must be on guard to not desire what does not belong to us. 

There’s A War Going On and It’s With Your “Flesh”

The second thing that’s going on in our hearts is that there is a war going on! Before we came to Christ our war was against God, there was enmity (or hostility) between us and the Lord. But now that we are at peace with God through Christ and born again of the Spirit our war is against our old fallen nature. We have died to it in Christ but it’s still here! 

It is the constant bane (the source of harm or ruin) of the Christian. The thing we struggle with everyday. Sinclair Ferguson describes it as a “squatter” and he says squatters are hard to evict. R.C. Sproul described our old nature as a chicken with its head cut off. It still thinks it’s alive! This is not to excuse our behavior but it is to remind us of the war going on and it’s with our flesh.. 

 Beloved, I urge you as sojourners and exiles to abstain from the passions of the flesh, which wage war against your soul I Peter 2:11

Have you ever felt like there was a war going on in your soul? Welcome to the Christian life! This is the big battle, the big burden and war for us as Christians all of our lives. We battle against passions of sinful sexual desires, anger, jealousy, greed, laziness, selfishness and other idolatries of the heart. Galatians 5 describes this war:  

For the desires of the flesh are against the Spirit, and the desires of the Spirit are against the flesh, for these are opposed to each other, to keep you from doing the things you want to do. Galatians 5:17

  

Understand The Seriousness of Sexual Sin 

The second truth that Jesus is saying to us (in regards to overcoming sexual sins of the heart)  is to understand the seriousness of sin and here specifically sexual sin. All sin is wrong and an offense to God. But there are some sins which are more serious than others. Sexual sin is one of them. 

As I mentioned earlier  sexual sins account for about one third of the sins of the flesh mentioned in Galatians 5. In I Corinthians 5 there is a list of sins that Paul lists that warrant possible church discipline. The first one on the list is sexual immorality. In Mark 7 where Jesus lists serious sins which come out of man’s heart at least 3 of them have to do with sexual sin. 

Concerning lusting in our hearts after another, Jesus said it’s better to lose one of the members of our body (and to stop sinning) than for our whole body to go into hell! That should get our attention. Remember this is the Son of God speaking to us!  

You might think, “I thought all my sins were forgiven?” when I come to Christ? Even the ones I still struggle with?” I thought when I trusted Christ that I was justified before God the Father? These statements are all true. So why is Jesus mentioning about going into hell for sexual sin - and sexual sin of the heart? 

First of all I think that Jesus is highlighting the seriousness of sexual sin. In first Corinthians 6 Paul does the same: 

Or 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. I Corinthians 6:9-10

Paul is speaking about outward sins. Most of us struggle at least against some of those sins in our hearts. But are we fighting against them? Do we feel remorse when we give into those sins? Not remorse for being caught but remorse because we have not pleased God? Now, I want to be careful here. There are certain sins (besetting) that we may struggle against all of our lives. The gospel gives us both the assurance that we are forgiven and that we have the power of the gospel to resist them. Yet we may have to put those sins to death until we go to be with the Lord. 

But if you are living in clear sexual sin whether it’s in your heart or external actions and not fighting against them you should be concerned (afraid). If you are a genuine Christian God is or will discipline you (for your good)  If you resist that discipline He may allow you to reap what you are sowing. That is a discipline that you do not want. Sins of the heart will eventually become sins that are acted out.  You do not want a shipwrecked life as a Christian. 

But one should also be afraid that if you are not fighting against sexual sins of the heart it may be an indication that you are not a believer. And if that is true you will not experience the discipline of the Lord so much as His judgment which will be unimaginably worse. 

Jesus is showing that for many people their desire for sin is so powerful that it keeps them from having relationship with God and thus leads to them experiencing God’s judgment and wrath. John D. Barry, Douglas Mangum, Derek R. Brown, et al., Faithlife Study Bible (Bellingham, WA: Lexham Press, 2012, 2016), Mt 5:30.

Now I know that is a heavy word. How do we respond to it? Well I think that first we realize that this heavy word is from our Savior. These are His words, the words of Christ. He does not speak them to castigate or condemn us but for our good. If you are a Christian hear His words and respond by taking serious the sins of the heart as well as external sins. 

If you are not a Christian, Scripture tells us you are dead in your sins and if you die in your sins you will spend eternity away from the presence of God and His wrath will be upon you. I appeal to you today to come to Christ, ask Him to save you from all your sins and then ask Him to help you fight against them. So how do we do that? 

Understand and Apply Vigilance 

There are many means of grace in defeating sin but we want to begin with what Christ is saying to us in this passage. I’m going to spend more time on this section because I think it’s really important, especially because Jesus spends two thirds of the passage addressing it.

We want to focus on the grace that comes from the words of Christ. What do we make of our Savior’s words about tearing out our eye or cutting off our hand if they cause us to sin? I think most of us would  agree that He is using some form of hyperbole, exaggeration to make a point. I believe vigilance is one word to describe what He is commanding us to do. It seems as if our Savior is saying that there are some sins that are so serious that we must take radical ruthless actions against. Vigilance is required to carry those actions out. !

The eye and the hand are usually the two “culprits” when it comes to sexual sins, so they must be disciplined. Jesus said, “Deal immediately and decisively with sin! Don’t taper off—cut off!  Warren W. Wiersbe, The Bible Exposition Commentary, vol. 1 (Wheaton, IL: Victor Books, 1996)

We must be ruthless in eliminating sources of sexual sin. Jesus is telling us that to walk in purity one must commit to a long term war against the temptations of the flesh. One can’t “play” with sin or temptation or be passive towards them.

In Proverbs 4 Solomon calls us to not only to external actions but to those that flow from our heart:  

 

Keep your heart with all vigilance, for from it flow the springs of life. Put away from you crooked speech, and put devious talk far from you. Let your eyes look directly forward, and your gaze be straight before you. Ponder the path of your feet; then all your ways will be sure. Do not swerve to the right or to the left; turn your foot away from evil. Proverbs 4:23-27

The Hebrew word for vigilance carries with the meaning of to diligently guard. One commentary describes is this way: self-examination under God’s eye. We must be vigilant in guarding our heart against sexual sins. So how and where should we be vigilant? 

Be Vigilant With External Circumstances

We must cut off any external forces that are aiding the desires of the flesh. If you like reading romantic novels that tempt you to have some type of fantasies that are sinful.  Ones that incite you to want something that God has not given you then stop reading them. 

If you can’t seem to get away from watching unholy things on your phone, get a flip phone that doesn’t have internet access. If you are tempted by interaction with a co-worker (even in your thoughts) seek to avoid them or limit the time you interact. Cutting off one’s hand means we take ruthless ways of dealing with circumstances that can contribute to our giving into temptation. 

Be Vigilant In Watching Over Our Heart and Mind 

Secondly we must be vigilant against the temptations to sin in our heart and mind and affections. Remember Jesus is specifically addressing sins of the heart. We are in a war. 

Victory over the desires of the heart, must be attended with painful exertions. But it must be done. Everything is bestowed to save us from our sins, not in them. All our senses and powers must be kept from those things which lead to transgression. Matthew Henry  

Prepare your mind for action.IPeter 1 

We are in a war and therefore we can’t walk around and be unaware of the battle for our mind and heart - for our soul. (If you were in a war zone). When something is affecting our heart in a way that we recognize is not of God we must deal with it immediately and decisively as  Scripture calls us to. 

John Piper remarks that when we face temptation it is the first 5 seconds where the battle rages. He states that we must exercise the muscle of our mind which for the Christian is supercharged with the Holy Spirit (not our own strength but by word and Spirit). We must train ourselves to deal with tempting thoughts and deceitful desires right away. This is a life saving exercise that we must cultivate. Piper tells us:  (That sounds good but how do we do that?)

When you are enticed sexually, do you fight with your mind to say no to the image and then mightly labor to fill your mind with counter-images that kill off the seductive image. John Piper
 

Be Vigilant To Kill Sin Through God’s Word 

How can a young man keep his way pure? By guarding it according to your word… I have stored up your word in my heart, that I might not sin against you. Psalm 119:9, 11

Now I know many of us are familiar with those verses. But here’s the question: are you actively doing this? I’m not talking about reading through the Bible which is a major means of grace. I’m talking about actively hiding and keeping specific verses in your heart and mind. Ones that speak specifically to the temptation and sin you are fighting against?  

In Ephesians 6 God’s word is described as the sword of the Spirit. How can we enter into a battle, engage in a war without having our main weapon? When Piper talks about filling one’s mind with counter-images they must be directly or indirectly tied to Scripture. It may be as simple as “that does not belong to me, God has not given that to me. But I believe it should also be tied directly to specific verses.

Verses like Titus 2
 

 For the grace of God has appeared that offers salvation to all people. It teaches us to say “No” to ungodliness and worldly passions, and to live self-controlled, upright and godly lives in this present age Titus 2:11-12 NIV

This is a promise from God, this is a refuge to run to. Do you have specific scriptures that you “run” to in your mind when you are tempted? You must be vigilant to do so. I believe you should also be vigilant in actively reviewing those verses on a regular basis. Exercising the muscle of our mind should be tied into scripture and the truth it brings to bear. Dr Lloyd Jones in one of his books says:

The main art in the matter of spiritual living is to know how to handle yourself. You have to take yourself in hand,you have to address yourself, preach to yourself, question yourself. Martin Lloyd-Jones.  

Sinclair Ferguson (Devoted To God: Blueprints For Sanctification)  says that we need to “tend the garden of our soul, weeding, planting, nourishing it patiently.”

Is it cruel to suggest that many of us spend more mental time and energy on fixing face and hair and mouth and clothes before the mirror than we do fixing our minds on the mirror of God’s word? We can hardly deny that we find it much easier to be engrossed in our hobbies and interests than in Scripture. Sinclair Ferguson 

Ouch. That is a sword that thrust through us all. We must commit ourselves to building habits into our lives and schedules that will help us pull out the weeds of evil desires and plant the seeds of God’s grace through His Word. James tells us 

 Therefore put away all filthiness and rampant wickedness and receive with meekness the implanted word, which is able to save your souls. James 1:21

This is doable but it does require work. Last week Daniel gave us a list of questions to answer regarding anger in our heart (which is another besetting sin for many). Fighting besetting sins requires what pastor Kent Hughes refers to as “holy sweat”. Spirit dependent effort that will yield fruitfulness and victory. 

Be Vigilant In Being Filled With The Spirit (Though Prayer)

It’s amazing (embarassing) to me how sometimes in regards to really important things in my life I can be very inconsistent (delinquent) in prayer. We can not afford to do that in battling sins of the heart. Are you being vigilant to daily call out to the Lord in prayer (fasting) for his grace. Do not overlook this means of grace. Have you ever heard the saying “The harder I work the luckier I get?” Here is the Christian version of that: “The more persistent I pray for something the more I see my prayers answered.” 

Being vigilant is very much in line with Scripture’s call to kill sin. Romans 8 tells us we are to do so by the Spirit. Galatians 5 states to us:  And those who belong to Christ Jesus have crucified the flesh with its passions and desires. That is they have learned to say no to the flesh and its impulses. They have learned to exercise the muscle of their renewed mind.  

Colossians 3 states: 

 Put to death therefore what is earthly in you: sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry. On account of these the wrath of God is coming . 7In these you too once walked, when you were living in them. 8 But now you must put them all away: anger, wrath, malice, slander, and obscene talk from your mouth. 

We must find God’s grace to put to death what is earthly in us. That comes through the empowerment of the Spirit in prayer, through filling our hearts and believing God’s word and through God’s people. 

Be Vigilant In Having Accountability 

Certain sins and temptations require regular consistent accountability with other Christians. The drastic action that Christ is calling us to in this passage may mean you regularly meet with another Christian or in drastic cases you may need to join  a support group where the other people in the group will help you grow in vigilance and to triumph over sin. . 

Conclusion 

I know that I’ve covered a lot, especially in the application area. I believe our text calls us to a vigilant life of watching over our hearts and minds. This will lead us to a happy fruitful life. Happy in the gospel that tells us that our sins are forgiven and happy as we experience victory over the sins of the heart. has been broken over us.