Dear friend,

Sex is like fire. When it blazes in the fireplace, a good fire warms and brightens the room, enhancing joy and companionship. But when fires ignite in the wrong places, the house burns down. Is your sexuality igniting in the wrong places? Are you treating sexual sin casually? How do you know when this has happened? Let me offer a few tests that can rouse your conscience.

  • Is what you are doing simply wrong? The outright evils of sexual immorality are not hard to identify. Our culture makes the water very muddy and preaches the doctrine that dirty water is good to drink. But the line between love and lust is clear. We are to treat other human beings in a familial way. You don’t ever sexualize a person whom you are called to treat as your brother or sister, your mother or father, your son or daughter. Sexuality is reserved for marriage. You are to protect other people, not lust after them. Consensual immorality is still immorality.
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  • Are you captivated by sex? One sure tip-off is that you are preoccupied. When something takes up too much airtime in your mind, when you’re driven, when you must do it, you just do it, you can’t help doing it, you can’t not do it—you’ve got a problem. Whenever sex becomes obsessive, impulsive, or compulsive, it’s going astray.
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  • Do you hide what you are doing? Hiding what you are doing and the time you spend doing it is another clear tip-off. Wrong doesn’t love the light (unless it’s become shameless and brazen). We hide when we know something is wrong. When you create a secret garden of any sort in your life, mutant things inevitably grow. So we hide from the eyes of others, from the eyes of our own conscience, from God’s eyes.
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  • Do you use sex as a refuge? Boredom, stress, loneliness, and pain tempt us to look for an escape. Do you try to flee discomfort or mask pain? We are meant to look pain in the eye, to grasp the experience, to bring it in hand to our God, to cry out for help, to find refuge, and then to do what can be done constructively, however seemingly small our powers.

If you are being nonchalant about your sexual sin, I hope that my list arouses a proper sense of unease. Fires are burning outside the fireplace. Is something not right with your sexual behavior? You are a child of light—don't walk in darkness! God’s point of view is good, right, and true. He beckons you. Walk as a child of light—for the fruit of light is found in all that is good, right, and true. The God who invites us into what is good also warns us off what is bad. You may be sure of this: everyone who is sexually immoral has no inheritance in the kingdom of Christ and God. Don’t let anyone deceive you with empty words. Because of these things, the wrath of God comes on the disobedient. That’s the gist of Ephesians 5:5–9:

For you may be sure of this, that everyone who is sexually immoral or impure, or who is covetous (that is, an idolater), has no inheritance in the kingdom of Christ and God. Let no one deceive you with empty words, for because of these things the wrath of God comes upon the sons of disobedience. Therefore do not become partners with them; for at one time you were darkness, but now you are light in the Lord. Walk as children of light (for the fruit of light is found in all that is good and right and true).

Take it to heart. Don’t let peer pressure or the culture deceive you. By the mercy of Christ, you will live a brighter, more loving, and more fruitful life.

How do you change? There are many facets of that big question, but I will point to four. First, the starting point for change is to say, “What I am doing is wrong.” That acknowledgement gets you pointed in the right direction.

But God doesn’t just tell you to shape up. The second step is to realize “I need mercies from my Father. I need him to love me and forgive me. I need his strength and forgiveness.” Recognizing wrong leads to awareness that you need something that only God can give you—something he freely gives. He gives himself in Jesus Christ.

The third step in changing is to act on this. The Lord calls you to seek him, to find him, and from him to receive what you most need. Psalm 25:11 brings this to life:

For your name's sake, O LORD,
pardon my guilt, for it is great.

Cast yourself on the care of your Father. Find grace and help from outside yourself. Seek, and you will find the mercy you need.

The fourth step is not really a step; it’s a lifestyle. It’s learning to walk out what those “good, right, and true” things look like. This has many different aspects that work out in our lives at different times. Choose to spend time with different companions. Put filtering software on your screens. Set up real accountability with someone you trust. Make the kind of lifestyle changes that get you out of the path of where you’ve gotten yourself into trouble. Jesus uses a vivid picture of how to deal with our own evil. If your hand causes you to sin, cut it off; if your eye causes you to sin, gouge it out. He shocks us into a radical amputation of evil. And of course, none of these battles are one-and-done. God intends to work in you a committed resolve to take seriously what’s wrong, to need him, to pursue what’s right. It’s an ongoing fight.

Here is one of the most helpful things I heard early in my Christian life. Think of your soul as a room. When you’re in sin, that room is full of dark forces, dark people, and darkness. There are two ways you get rid of darkness in your soul. One way is to cast it out, fight it, resist and reject it. The other way is to fill the room with light. As your life fills with better people, better things to do, and more reasons to live in the light, then there’s less room for the darkness.

Jesus Christ gives a beautiful call. He invites you to live a radical life. He challenges people who think that it’s okay to do wrong. He challenges people who think they have moved past outmoded cultural values. He challenges people who think that current cultural assumptions are good, right, and true. Don’t go along with the crowd. Don’t drift with the culture. Do what Flannery O’Connor said we should do: “Push back against the age as hard as it pushes against you.” Live out in the daylight, not in the shadows and darkness.

Finding the mercies of Christ and learning to walk in his light is courageous. It has an impact on people around you. You demonstrate the Lord. That’s bigger than any one of us individually. In a world where the light is going out on sexual rights and wrongs, you have an opportunity to turn on the lights.

—David

This letter originally appeared on Crossway.com.

David’s book, Making All Things New, was released by Crossway in August 2017. Purchase your copy here.