The Heart of Adultery

In the Sermon on the Mount, Jesus takes the commandment, “You shall not commit adultery,” and intensifies it:

“But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart.” (Matthew 5:28)

This statement forces us to move beyond mere external obedience and examine our hearts. While avoiding physical adultery is good, Jesus calls for something deeper—a transformation of our desires.

What Is Lust?

Lust is not merely noticing someone’s attractiveness. The Greek word Jesus uses refers to a deep longing or craving. It is an ongoing, intentional gaze that reduces a person to an object of personal gratification. Lust isn’t just about sexual desire—it’s about taking, consuming, and using someone for our own benefit. You can lust for power and use people to get ahead. You can lust for money and use people to line your own pockets. You can lust for popularity and use people to climb the social ladder.

This pattern of destructive desire is as old as the Bible itself. In Genesis 3, Eve saw the fruit, desired it, and took it. The result? Catastrophic consequences. This is what lust does—it distorts our perception of others, making them objects to be taken rather than people to be loved.

A tragic example of this is found in 2 Samuel, when Amnon lusts after his sister Tamar. His so-called "love" is nothing more than a selfish craving. When he finally gets what he wants, he discards her in disgust. Lust is the opposite of love—love gives, while lust takes. Love asks, “What can I do for you?” while lust asks, “What can you give to me?”

Jesus' Radical Solution

Jesus offers a striking warning:

“If your right eye causes you to stumble, gouge it out and throw it away.” (Matthew 5:29)

This is not a call for literal self-mutilation, but rather an urgent command to remove whatever is leading us into sin. If something is causing us to see others as objects rather than image-bearers of God, we must be willing to take drastic action to change.

Jesus contrasts this with Gehenna—a real place outside Jerusalem associated with child sacrifice. In the Old Testament, people sacrificed their own children to false gods in pursuit of their desires. Gehenna, then, becomes a symbol of deep, unfulfilled longing—a warning that unchecked lust leaves us perpetually empty.

How Do We Change?

Jesus does not simply demand change—He provides the way for transformation. We cannot fix our hearts by external means, whether by covering everything in rules or by sheer willpower. Instead, we need new hearts.

The solution Jesus offers is not about managing behavior but about reshaping our loves. He calls us to see others as fellow image-bearers, not as means to an end. And ultimately, He offers Himself as the sacrifice for our broken desires.

If we want real change, it starts not with self-discipline alone but with coming to Jesus, the only one who can truly make our hearts new.