DESIRES. WE ALL have them; it’s part of our human nature. Our bodies are wondrous and complex, and our desires are meant to point us to what our bodies need. We would not survive, for example, without the gnawing feeling of hunger that drives us to seek food, nor the sense of pleasure and fullness that comes from satisfying that desire. Conversely, feelings of revulsion and pain help us steer clear of things that might harm us. All of this and more is part of the gift of how God created us to be.

But as the Old Testament sages knew, desires could be like forces that drive us toward or away from God and a life of righteousness. And today, we can’t afford to be naive about the ways in which the world constantly plays upon and manipulates our desires in order to sell us something.

Here’s one seemingly innocuous example: the humble potato chip. Potatoes themselves are a good and nutritious food — but I doubt that anyone would call them “addictive.” The potato chip, by contrast, is intentionally engineered to be addictive by appealing to and overstimulating our bodies’ natural desires for fat and salt.

Advertisers have even flaunted the fact. Commercials for Lay’s Potato Chips once challenged viewers with the slogan, “Betcha can’t eat just one.” Later, comedian Jay Leno hawked Doritos Tortilla Chips and encouraged viewers to “Crunch all you want; we’ll make more.” Obviously, your body doesn’t need chips to survive. But it can be manipulated to crave them. You want to experience the pleasure of eating them over and over, mindlessly munching until the whole bowl is empty and it’s time to add chips to your shopping list. So crunch all you want; there are lots of companies making more, and you just have to be willing to pay for the privilege.

The age of electronic devices — especially portable ones! — that can access the Internet has upped the ante. The hot commodity is now your attention, or as marketers sometimes call it, “eyeballs.” The game is this: when you go online, who can get you to look their way? Who can arouse your desire or curiosity enough to make you click their link?

Pop-up ads, for example, keeping putting things in front of you that you looked at before while browsing but didn’t buy. Hey, remember me? they seem to say. Are you ready to buy me now? You know you want to… Or take the ubiquitous ads for products to help you lose weight simply and quickly. They tease you with outrageous claims about some miraculous life hack that makes you just curious enough to click. And of course, as marketers have long known, sex sells. Images of attractive and desirable people are used again and again to get us to pay attention, as if somehow buying the company’s service or product would get us a wink and a smile from some hottie.

It’s ridiculous when you think about it. But that’s the point. We don’t think about it, and we’re all too ready to play the game.

Here’s one important implication of all this: your attention is valuable. You get to decide what to do with it. And it matters where and how you direct it.

THE SIXTH AND seventh of the Ten Commandments prohibit murder and adultery, while the tenth prohibits covetousness. As we’ve seen, Jesus illustrates the kind of righteousness appropriate to the kingdom of heaven by reinterpreting what his hearers had been taught about murder. Now, he turns to the commandment about adultery:

You have heard that it was said, “You shall not commit adultery.” But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart. (Matt 5:27-28, NIV)

People might confidently believe themselves innocent of murder in the sense of the legal definition of homicide. But who is innocent of angry contempt? And people might confidently believe themselves innocent of adultery because they’ve never physically cheated on their spouse. But who is innocent of lust?

It’s important here, I think, not to see this solely in terms of someone drooling over pornography. The word that is translated here as looking at someone “lustfully” is the same word the apostle Paul uses twice in the book of Romans to refer directly to the tenth commandment: “You shall not covet” (Rom 7:7; 13:9). Jesus, in other words, is redefining adultery in terms of covetousness, in terms of misdirected desire.

And nobody is innocent of that.

LET ME SUGGEST one important concrete application of this — and fair warning, some may find it offensive. Many of us have struggled in our marriages. We don’t feel seen or heard, loved or cherished. We want someone who will give us the attention and compassion we crave.

Then, someone other than our spouse sweeps into our lives like a breath of fresh air. They look at us kindly; they listen to our complaints patiently. They tell us how good and brave we are to put up with our spouse’s nonsense. And before long, we find ourselves wanting that person’s company; we look forward to being with them in a way that we no longer do with our spouses. With them, we feel safe. With them, we feel understood and valued for who we are.

Of course, we would never let ourselves actually sleep with them, even if we wanted to. We know that’s wrong. No good Christian would cross that line. So we’re not guilty of adultery, right?

Well, what do you think Jesus would say?

If we take righteousness as a matter of following a set of behavioral rules, then no, we haven’t committed adultery if we haven’t been sexually unfaithful. But extramarital affairs aren’t just physical; they’re emotional. And when we begin to become romantically attached to someone other than our spouse, we are already being disloyal and unfaithful.

Jesus recasts adultery as a matter of the heart. And the heart question is, do we want something that doesn’t belong to us, that isn’t ours to have?