“Whoever Lusts” - Part I

Matthew 5 and the Second Antithesis on Adultery

Well, this morning we are actually continuing on with Matthew 5 and we'll be looking at verses 27 and 28. This is part one of what we'll conclude, Lord willing, next week with verses 29 and 30. And as it's part one, we're going to be a little more general than perhaps we'll be next week.

There's still going to be all sorts of practical advice that I hope you'll be able to apply into your lives, but I want you to realize we are being a little more general than we'll be next week. Next week we'll sort of drill down into some actually concrete applications that are far more specific and I think far more practical.

But in order to do that well, we really need to build a strong foundation and that's what I hope to do this morning. So we are looking at Matthew 5, 27 and 28 as we shift now to the second antithesis.

Remember in the Sermon on the Mount, we've come through the Beatitudes and Jesus' explanation or prelude into how the law relates to the kingdom. We understand that now He's moving forward to a series of six antitheses.

You have heard it of old, but I say to you, and here we see Jesus using His authority as the Lord of the Sabbath, as the Lord of the law, the lawgiver Himself, not innovating or establishing something new, but revealing what has truly been given by God.

And so with Matthew 5, 27 and 28, we begin the second antithesis. You have heard that it was said to those of old, you shall not commit adultery. But I say to you that whoever looks at a woman to lust for her has already committed adultery in his heart.

All right, Matthew 5, 27 and 28. So Jesus quotes the seventh commandment, you shall not commit adultery. That's from Exodus 20, 14. As Jesus clarifies what the commandment forbids, He explains that to even look at a woman with lust is to already commit adultery with her in the heart.

This is the same way as we saw in the first antithesis, to look at a brother out of anger, to have anger in the heart is the same as to murder him. In other words, the seed may for many reasons not come to fruition, but it is still the same act, therefore still the same transgression.

It still breaks the commandment of God. So Jesus stresses that this transgression, even though it falls short of action, has nonetheless taken place. It's not occurred relationally, but it has occurred in the heart.

In the heart, there is a genuine motive. The motive lacks opportunity, but there nevertheless is a motive. And that motive may not come to fruition because there is a fear of consequence, but it's a real motive, and it really breaks the commandment of God.

This is not a sarcastic exaggeration. Jesus is not speaking hyperbolically. He's not saying, well, can you imagine if this was really the case? This really is the case. It really does break the commandment of God.

John Owen, in his tremendous book, and I'll be referencing this a lot over the morning as well as next week, Mortification of Sin, where John Owen really takes the surgeon's scalpel into putting sin to death, overcoming sin in our lives.

In fact, it was the great Scotsman, Rabbi Duncan, who, when he would pass out the copy of John Owen's Mortification to his students, would say, gentlemen, prepare for the knife. In other words, some things are going to get lopped off, and you're going to have to plunge this knife into your life, and it's going to be painful, but it will bring a good end.

And John Owen, in Mortification of Sin, says, sin always aims at the utmost. Again, we're connecting even the thought, even the motive to the actual transgression of the command. Sin always aims at the utmost.

Every unclean thought or glance would be adultery if it could be. Every covetous desire would become oppression. Every thought of unbelief would become atheism if it could be grown to its height. That's exactly what Jesus is saying here in these antitheses.

I say to you, whoever looks at a woman to lust at her has already committed adultery.

Full stop.

That's what Jesus is saying. Now the verb for lust here, in the Greek, it's an interesting term. There's a few different terms that could have been used, and Jesus uses a Greek verb that doesn't usually depict only lust, but can speak of just any sort of strong desire.

The Greek verb here is epithumeo, a strong desire, an intense desire, a passion. This can be used negatively or positively. A strong desire to seek after the Lord, that would be the same verb here. And perhaps that's very intentional, that we understand what a strong desire should be toward and what it should not be toward.

Now here it's very important, the seventh commandment, God forbidding adultery, Jesus, by using this verb, I'm convinced it's connecting it intentionally to the tenth commandment. A tenth commandment is, you shall not covet.

You shall not desire what does not belong to you. You shall be content with what things you have. You shouldn't desire your neighbor's house, nor his wife, nor his male servant, nor his female servant, nor his ox, nor his donkey, nor the stranger within his house.

You shall not covet. And so with this verb, we actually have the tenth commandment framed in view because that word covet is the same word in the Greek. So in the Septuagint, in the Greek translation of the Hebrew, that's the verb that's used.

You shall not strongly desire. You shall not covet. Here we could almost say, I say to you, whoever looks at a woman to covet her has already committed adultery. So here we have the idea of lust or adulterous desire being connected with covetousness, the tenth commandment.

It's the same word in Galatians 5 .17, the desires, the covetings, the strong passions of the flesh are against the spirit. And the desires, same verb, strong passions, strong desires, strong covetings, the desires of the spirit are against the flesh.

And these two things are opposed to each other. In fact, if you take the time to look at any number of scriptures, you'll find that where sexual morality is in view, where lust is in view, it's often not far from covetousness.

Hebrews 13, 4 and 5, this is one of many examples. Marriage is honorable among all in the bed undefiled, but fornicators, adulterers God will judge. Let your conduct be without covetousness. We read that often as if he's gone on to the next topic, but again, there's this link between the idea of covetousness and sexual immorality.

The tenth commandment deals with desire in this way. You shall not covet your neighbor's wife. Isn't that what Jesus is saying here in Matthew 5, 27 and 28? The early church, ever since this issue came to the fore, the early church has spent a lot of time theologizing and the impact of that theology in terms of transforming the Roman Empire, a culture that was suffused with sexual immorality.

And by the time Christ was enthroned in people's lives and whole cities began to be turned inside out, you find that actually there's a massive shift away from any sort of sexual impropriety. Where Christianity had allowed its salt and its light to flourish, there was all sorts of new measures passed in how one was to regard marriage, how to regard a neighbor.

It wasn't just the coliseums that closed down, but even the brothels. And so the medieval theologians especially, they began to have a special term for this covetous desire as it related to desiring another person sexually.

And that term is concupiscence, a very fancy term. And the issue that they wrestled with is, of course, there is a healthy desire in this way, but there's also aspects of it that are sinful, and how do you distinguish between what is right and what is sinful?

When is it right to have this desire, a desire found, say, in Song of Songs, a desire from the beloved for the beloved? And so in the same way, you have to wrestle through when and what does this desire look like when it's right, when and what does this desire look like when it's wrong?

And sometimes we literally press into the when. When is it right? It's a lot about timing as much as about object, about relationship. But we have to begin with the right in order to establish what is wrong.

We have to lay down what is true, what is good, what is upright in accords with God's design if we can then look at the deviation, the straying, the transgression, the mutilation of what God has given us.

So the problem, and we're going to begin here, the problem is not God's good design. That is not the problem. What God designed, God declared good, very good. The problem is not God's design. The problem is not the goodness of desire when it follows God's design.

That's not the problem. The problem is not desire when it follows God's design. It's a good desire. It's a good thing. God declared it good. We may blush when we understand some of the poetic metaphor in Song of Songs.

God doesn't blush.

He created it.

He revels in it. The problem, again, is not God's design nor a good desire that follows God's design. The problem is the disorder of that design. The problem is the perversion of that desire. That's the problem.

We always begin with the good design before we examine and reject its malformation, its.

Abuse.

It's very important that we do that practically. Don't begin with what's wrong. Begin with what is meant to be right. Then you can actually understand what has gone wrong. Physical intimacy is not merely permissible, and we shouldn't speak of it in that way.

We'll just say, okay, I guess I'll allow this. I guess I'll give you a few conditions in which this desire can be satisfied. Physical intimacy is not merely permissible. We shouldn't approach it like it's some loophole, some strange thing that belongs to humanity, something that should be spoken about in hushed tones.

No.

God designed it.

God blessed it.

God gave it as a gift to be enjoyed, but a joy according to his design, which is within marriage. Ian de Goode, in his introduction to his commentary on the Song of Songs, he says, when the Shulamite in the song dreams of her lover, she does not imagine them sharing an inductive Bible study and praying together.

In other words, there's nothing less holy about the intimate desire in Song of Songs than say desiring after a Bible study and a strong prayer life together. This is as holy, as good, as blessed as the other.

We have to begin there. She's daydreaming not about a Bible study and praying together. She's dreaming about her lover's embrace, and it's precisely this desire that her community, the daughters of Jerusalem, are actually celebrating.

Now, of course, Song of Songs is written as love poetry, but we understand it's in the Word of God as a canon because it does preview and portend the love between the church and Christ, according to that beautiful Ephesians 5 imagery, some of which we'll discuss next.

Week.

So the problem is not God's good design or even the goodness of desire that follows his design. The problem is when God-given, God-oriented desire becomes out of bounds. It becomes disordered. It begins to rule in our mind, in our affections, and in our will, rather than God ordering and ruling in our mind, in our affections, and our will, which allows that desire to be in its proper place at its proper time.

As D .A. Carson rightly says, what Jesus exposes in these verses is not a prohibition of the normal attraction which exists between men and women, but of the deep-seated lust which consumes and devours, which mentally contemplates and therefore commits adultery.

Jesus speaks these words into our world. Jesus speaks these words into a world submerged into lust. 1 John 2 says, all that is in the world, the lust of the flesh, the lust of the eyes, the pride of life, it's of the world, not of the Father.

We live in a world parallel with the fall, as 1 John 2 is actually parallel with the.

Fall.

The woman saw the tree was good for food, that's a desire of the flesh, pleasant to the eyes, that's the lust of the eyes. And a tree to be desired to make one wise, that's the pride of life. We live in a world parallel with the fall.

We live in a world submerged into the lust of the flesh, the lust of the eyes, the pride of life. And is this still a timely message to hear? Well, haven't we all been somewhat stunned of the events, even a few weeks ago?

We're not perhaps as stunned when some health and wealth preacher has some moral collapse and abandons their ministry, but when, if we could put it this way, when one of our.

Own falls.

How many ministries have fallen in the disgrace of sexual sin just in the past five years?

It's stunning. It's stunning.

Lust has become a way of life in our culture. There's absolutely no shame about it at all. In fact, if you can monetize it, more power to you. If you can gain a platform out of it, more power to you. Lust has become an absolute way of life, a way of doing commerce even.

And therefore, Jesus' call in these verses is all the more jarring and costly, especially as next week as we drill into some of the details. Jesus has some stark words to say about what it requires to enter the kingdom.

It requires, as it were, the same force and willfulness to maim yourself, to gouge the eye, to cut the arm.

That's where we're going.

Jesus' words are costly. Jesus' words are challenging. Jesus' words are not to be taken lightly. Whoever looks at a woman to lust for her has already committed adultery in his heart. Let no man think, as John Owen says, he has made any progress in holiness who does not walk over the bellies of his lust.

For not putting sin to death, as Owen would say, sin is putting us to death. So, there's a call in these verses, and that's how I want to frame some of our application this morning. Again, being very general in order to build a foundation for where we're going next week.

And I want to frame that at the beginning here two ways. First, there's a call to men as beholders, the call to the beholders. And I'll explain that in a moment. And secondly, we'll address the ladies with those that are being beheld.

There is a call to those that are beheld. And I like this dynamic of thinking of men and masculinity as that which beholds and thinking of women and femininity as that which is beheld. I think that's very helpful, and I think it accords very well with the way that God created us.

Adam, of course, was not created to be beheld by donkeys and oxen. He was alone. The first time that God said something isn't good. But he recognized that in that not being good, there was a second helper, a counterpart to be given to Adam.

And so, out of Adam, out of the Adam's riven side, came forth a bride. Now, Adam, who alone in creation had been left to himself, had an equal, had one that his heart could praise and delight in, one that he could behold.

And in beholding her, he sprung out into song. He was absolutely beside himself. He had found the very flesh of his flesh, the very bone of his bones. And they became one. So Adam was the beholder of Eve.

And Eve was created, in many ways, to be beheld by Adam. And this everforth has been the dynamic that God intends between a husband and his wife becoming one flesh. So speaking to men as those who behold.

The Westminster Confession of Faith, I actually think is very helpful, or I should say the larger catechism. Question 138, where it's going over the duties required by the Seventh Commandment. I'm not going to touch on all of them, but on several of them.

So the answer given is, again, what duties are required by the Seventh Commandment? Here's the answer. The duties required in the Seventh Commandment are chastity in body, mind, affections, words, behavior, to be chaste, to be pure in the way that we think, in the way that we react, in the way that we speak, in the way that we carry ourselves.

The preservation of it in ourselves and in others. You do what you can to help others be chaste in these very ways. Watchfulness over the eyes and all of the senses. Temperance. The keeping of chaste company.

In other words, good company reinforces good morals. Bad company corrupts good morals. Modesty in apparel. Marriage by those who don't have the gift of continency. In other words, those who aren't able to endure a life of singleness or celibacy.

Conjugal love and cohabitation. That's belonging to marriage. Diligent labor in our callings. Shunning every occasion of uncleanness. Resisting temptations thereunto. Those last two points we're really going to drill into next week.

But let me pull out several of these that I think are important. First, watchfulness over the eyes and the senses. This is a call to beholder. And what do beholders do?

They look. They behold.

They look with their eyes. They see with their imagination. And if Jesus is addressing anyone, he's addressing men that behold. If any man looks, that's who he's addressing. And so, keep a watch over your eyes and over your senses.

Your senses play into your sight. Your senses play into your imagination. In fact, the more involved your senses are, the more energized your imagination becomes. It becomes charged with what you've experienced bodily.

And sometimes our sight is actually charged with the memories of other physical sensations. So it's not just the eyes that we guard, but indeed all of our senses. Remember what Job said when he's recounting his sort of defense claim against the accusations of his brethren.

Surely there's some sin in your life. And he's going and he's surveying every aspect of his life to say, No, even here, I don't really find any guilt or any offense before God. And one of the things he says in 31 is, Listen, I made a covenant with my eyes.

Why would I look then at a young virgin? Why would I look at a young maiden? So you see, even Job, even this ancient brother, as it were, understands the significance of guarding his eyes. And he puts it in covenantal language.

I made a covenant with my eyes that I wouldn't look, that I wouldn't behold, that I wouldn't allow my imagination to stir, that I wouldn't allow my glance to drift, that I wouldn't allow my thoughts to linger or my reaction to somehow imprison me.

You find John Bunyan in this book that deserves to be as, I think, popular as Pilgrim's Progress,.

But Holy War.

Some years ago I began reading through that with Joshua Harrison. He was championing, and I had never heard of it. It was tremendous. And in Holy War, John Bunyan gives an allegory of the fall of man.

He has this town called Mansoul, and the whole story of Holy War is about the sort of fall of Mansoul, the sort of Prince Diabolus, the devil who comes and deceives them, and they fall, and they now lash out in rebellion against the Prince Emmanuel, against the good king of that land.

And in their rebellion, of course, throughout the storyline, the Prince undertakes to save them again. And so you see Mansoul as it was created, and then as it fell, and then as Prince Emmanuel does what is necessary to restore it.

It's a beautiful allegory that has all sorts of insight into Scripture. But one of the things he does is he allegorizes the city of Mansoul as a body. And so you have eye gate and ear gate and mouth gate.

And as sin assaults, as temptation comes, you see that different reinforcements are needed at the eye gate, or at the ear gate, or so on. Very, very insightful. And we need to understand our bodies in that way too.

Scripture likes to speak of our eyes as windows, likes to speak of our eyes as gates. If you were living in the ancient world, the gates were your primary defense mechanism. You can close those gates, and the city that is walled remains secure.

The gates are the weakest point. If you were going to besiege a city, you would put all of your assault works toward the gates. If the gates can hold, the city will hold. But if the gates fail, then everything else will be lost in a matter of time.

Thus we see, as Calvin says, the eyes are like torches that inflame our hearts to lust. Senses readily embrace the occasions of sin which are presented to them, and they convey it to the mind. We could think of the mind as the citadel.

What you allow through your gates is eventually going to topple that citadel. So you have to put a guard at your senses, at your eyes.

You keep a watch.

Wherefore, let everyone endeavor sedulously to govern his eyes, Calvin says, his ears, unless he wishes to open so many doors to Satan, to the innermost affections of his heart. Too often we allow the gates, brothers, too often we allow the gates unlocked, wide open.

And we think, we'll make a rally at the citadel. Well, it's too late. It's too late. You take your stand not at the very end of the battle, but before it ever begins. You take your stand at the gates.

Keep a watch over them. And recognize this. Sight enables imagination. And so men especially have to be conscious of the way their eyes are enabling sinful thoughts. That's why Job made a covenant with his eyes.

Our eyes allow us to create and retain images and feelings that ought to belong in marriage alone. And sometimes they don't even belong in marriage, frankly. Guard the gates of your very soul. Your eyes, your ears, your senses.

You recognize that whatever you don't feed will starve. Whatever you don't feed will starve. And so you don't keep allowing fuel into imagination that is polluted. You cut off the supply. You close the gates, as it were.

Whatever doesn't allow food through will eventually starve out the corruption within. It's another image that comes from siege works. You would surround and besiege a city, and you're essentially cutting off vital supplies.

And if food and water and other things can't be wrought in the city, in a matter of time it will be destroyed. In that sense, if you have a corrupted mind, if you have a stained conscience, you need to cut off the supply.

Allow it to starve.

Whatever you don't feed will starve. Be watchful of your eyes and your senses. Part of this relates to what we considered even last week. How do we regard one another? How do we think of one another? 1 Timothy 5.

Rebuke not an older man, and treat him like a father, and with younger men like brothers, with older women like mothers, with the younger as sisters with all purity. It's the first qualification we get in that list.

Treat everyone in the church like this, like you're related to them, like they're a sibling. If they're older than you, treat them like a mother or a father. But notice what he says about young women, brothers.

Treat them like sisters with all purity.

With all purity.

How do you regard? You're sisters. Not as sisters, or as sisters with all purity. Keeping chaste company, second point drawn from question 138. Keeping chaste company. If you would guard your thoughts, you have to guard your companions.

Now, some of this is out of your hands, right?

Who you work with.

And I worked at a factory for seven years. I worked with long-haul truckers coming from all parts, Midwest and West, and heard words that I didn't even know were vulgar. Things that I was like, I don't even want to look that up.

I don't even want to know what that means. So sometimes you can't control the people that you're around, but I would argue you can control your companions. Who you happen to be around is different than who you walk with.

Keeping chaste company is necessary if you would keep your life chaste. Guarding your thoughts means also guarding your conversations. Guarding your imagination doesn't mean just guarding your eye gate, but guarding your ear gate.

What things are spoken about? How are people spoken about? How are experiences spoken about around you? This also can corrupt your imagination. In that sense, brothers, be very mindful of what you're allowing your ear gates to welcome.

It's not just physical companions, but even the companions of podcasts, and films, and music, themes, lyrics, conversations, memories that are being relayed. These things too are allowing the gates open to the citadel.

Now this doesn't mean just simply shunning, but as we say, keep chaste company. So it's not just the relationships you're avoiding in order to maintain a life of purity, it's also the relationships you're building.

You don't simply put off relationships that will make it difficult for you to remain pure. You actually pour time in building relationships that will help you keep pure, that will reinforce your desire to be chaste before the Lord.

And so you question, and even within the church, what relationships will help me to pursue holiness? What relationships do I need to invest in that will help me to walk straight, upright, pleasing to the Lord?

Third point, we're being very brief here, again very general. Third point I draw from 138 is the usefulness of marriage. Very important. Marriage, as they say, marriage, conjugal love, cohabitation. This too is given as a means for men to walk in purity.

We have in 1 Corinthians 7, because of sexual immorality, notice what Paul is saying, because of sexual immorality, let each man have his own wife, and let each woman have her own husband, and let the husband render to his wife the affection due to her, and likewise also the wife to her husband.

So this is Paul's very practical engagement with the need for marriage as a defense against sexual immorality. If it's because of sexual immorality, let the husband and wife be affectionate to each other.

That's what he says. Let them marry, and let them give proper affection to each other. And this is because of sexual immorality. Now the problem in marriage is so often, when there is sexual immorality, it actually blows up the affection that is shown between a husband and a wife.

Where there is a struggle, rather than using 1 Corinthians 7, that great insight, as a recourse to improvement or to help, it actually makes following 1 Corinthians 7 very difficult. So where there is a struggle with sexual immorality, a husband may feel like, I really need to run and retreat to my wife, but maybe he's not treating her with affection in that way, he's simply wanting to pursue her as a means to an end.

He's like, I don't want to struggle in this way, so I'm going to pour myself out toward my wife. Meanwhile, she's running away, she's getting the fire hose, get away from me. There's not any affection being shown, you're treating me as a means to an end.

And all of a sudden you see that even avoiding sexual morality has caused dysfunction in conjugal love and cohabitation. In other words, the marriage is not running as it ought to. But notice what Paul is saying.

In some ways he's saying, listen, the best defense is a strong offense. The best defense is a strong offense. Don't you get that sense in reading Song of Songs? It's like, this man is absolutely obsessed with the Shulamite.

Who else is he going to look to? Who else is he daydreaming about? Who else is he writing about? He's drunk with love, you could almost say. And in that sense, the hooks of temptation aren't really able to pierce him.

And so marriage is meant to be a defense against sexual immorality in this way. That doesn't put pressure on a wife in a way that somehow the husband's sins become her sins because she's not showing due affection.

No, no, no. But rather it does say that there's an immunization that comes with marital affection. And so in the general way that you occupy your lives together, recognize that one of the ways you'll be able to walk in purity is by simply enjoying the gift as it's given in marriage.

By showing affection and becoming intimate with one another regularly. Scripture has a lot to say about that. Paul seems almost to be blunt. You could almost take it offensively. Because of sexual morality, just make sure you occupy yourself with your wife.

And it's kind of like, well, it's not very romantic, Paul. It's kind of blunt. It's kind of almost offensive. But Paul has a lot more to say about the theology of marriage. Here he's just giving a really concrete piece of advice.

And you should remember that. You can have a much more elaborate view. And marriage means a lot more than this. But when it comes to walking in purity, Paul's advice is don't withhold. Be intimate. Be affectionate.

Because of sexual immorality, that's his advice. Marriage is not treated merely pragmatically as if it's just about use. No, no, that's what lust does, not what marriage does. Lust is about use. Lust is about a means to an end.

Marital intimacy is about a covenant, about a commitment, about two becoming one flesh. The stain of sexual morality works its way into marriage in that lust is just applied to someone that you actually belong to rather than someone that you don't.

But brothers, we have to completely understand there's a world apart between lust and temptation sexually versus marital intimacy. The two are like oil and water. They have nothing to do with each other.

C .S. Lewis makes this point so well. In writing his book, The Four Loves, he has this to say. We use a most unfortunate idiom when we say of a lustful man prowling the streets, he wants a woman. Someone who's lusting, he's desiring, he's burning with desire, you could say.

And Lewis says it's a very bad way that we speak about that man when we say he just wants a woman. Strictly speaking, a woman is just what he does not want. He wants a pleasure for which a woman happens to be necessary.

How much he cares about the woman, as such, can be gauged by his attitude to her five minutes after fruition. I trust you can read between the lines. Now, eros, here he's speaking of, there's different words for love, right?

Philia or agape love, and there's eros, erotic desire, erotic love. Not in some seedy, sort of gutter kind of way, but in some ways this intense romantic desire. And he says eros makes a man really want.

So the man who's burning in lust, prowling the streets for anything to occupy himself with, we say he wants a woman. Lewis is saying, no, he doesn't want a woman at all. He wants a means to an end. He doesn't want a woman.

But eros, desire, the right desire, that man really wants a woman. But not any woman, one particular woman. In some mysterious but quite indisputable fashion, Lewis says, the lover desires the beloved herself, not merely the pleasure she can give.

That's the difference between lust and marital intimacy. The lover desires the beloved. The beholder desires the beheld. Not merely the pleasure that she offers. Lust can only frame attraction as a glimpse.

It's a moment divorced of all context. Lust frames attraction as a glimpse, as a snapshot, as a browser window you can close a few minutes later. Not the whole. There's not a context of a life lived, of a soul formed, of a life engaged, a life that has had many different intersecting relationships, of one that belonged to one household but now is part of another, of a life that continues on after, even ever after, beyond to a hope and a promise that is sure.

Lust cuts off all of that and only wants to see in a moment, in a glimpse, in an encounter. It doesn't want to consider anything prior nor anything after. So there's no sequence of life beforehand. There's certainly no sequence of life afterward.

All the entailments of the life are cut off by lust. You're simply an object. That's what lust does. It objectifies. A means to my desire. A means to my end. Paul has a very deep theology of marriage.

If all he had to say was, listen, if you're struggling with sexual morality, just get married. If that's all he had to say about marriage, we would say, oh, he was very weak on his theology of marriage.

But Paul has a lot more to say about marriage, doesn't he? In fact, one of the things he says is, no one ever hated his own flesh, but he nourishes it, he cherishes it, just as the Lord does the church.

And we're members of his body, of his flesh, of his bones. And for this reason, a man shall leave his father and mother, be joined to his wife, the two shall become one flesh. And you see the relation between nourishing and cherishing the flesh that now is actually one with you.

That's the idea of marital intimacy. Nourishing, cherishing your own body, because now your body has been joined to the body of another. Nourishing and cherishing one's body overlaps to the marital union, in other words.