I love my city, London, and I am proud to live in it. I love its energy, its creativity, and its glorious multitude of cultures.

But there is much which distresses me about London: the extremes of wealth, the obsession with “stuff,” and the sexually saturated atmosphere. My journeys on the London Tube bring me face to face with ads featuring attractive women dressed with little left to the imagination, as well as offers to sort out any erectile dysfunction. My Metro, a free newspaper, offers me “personal services.” The phone app Tinder invites me to “hook up” with any available woman within a five-kilometer radius.

That’s just London, you might say. Yet even your teenager, safe in his or her bedroom “doing homework,” has London and worse just one click, swipe, or tap away. According to the Porn Scars initiative, one third of ten-year-olds have viewed pornography online, while the largest group of internet porn viewers consists of children age twelve to seventeen. Sex has become an industry in which people are translated into a commodity to be bought and sold, or, slightly more subtly, to be used to sell products.

Against this backdrop, how does the two-thousand-year-old teaching of Jesus apply now? He told his Jewish audience: “You have heard that it was said, ‘You shall not commit adultery’” (Matt. 5:27–30). But he doesn’t leave it with a prohibition of an external act. He raises the bar: “But I tell you, anyone who looks at a woman lustfully has already committed adultery with her in his heart.”

Right actions are not enough; what is going on in the head matters equally. Sexual sin starts in our minds when we treat someone made in God’s image as an object of gratification. Jesus will not allow such a dehumanizing process, in which real people – a stranger on the bus, a colleague at work, or a member of our church – are used to feed our sexual appetite. Whether it’s looking the wrong way or dwelling on inappropriate options, it falls into the head space called lust.

So what can we do? To some of us, Jesus’ teaching may seem impossible. Perhaps we can start by recognizing our profound need of God’s help. Then, relying on his abundance of grace, we can take a few practical steps:

Let’s ask God to help us to see people as individuals made in the image of God, refusing to allow them to become “things.”

Let’s avoid those particular situations which we know make us vulnerable.

Let’s regard that unwelcome thought, that doorway to lust, as an enemy rather than a friend. A quick prayer in Jesus’ name will often see it go.

Finally, let’s keep accountable. Have someone in your life whom you will tell about your own struggles, however embarrassing it might feel. Bringing these issues to the light breaks their power, because light and darkness cannot coexist.

The amazing truth that Scripture reveals to us is that God understands. Jesus was tempted in every way we are, yet without sinning (Heb. 4:15–16). He doesn’t leave us on our own, but promises to be with us through his Holy Spirit. We can learn to lean into him and find strength to make the right decision.

However bad our past missteps or our present struggles and sins, forgiveness is available. We don’t have to live with our guilt. Jesus comes to us, forgiving us and equipping us for everything we face, no matter where we live. Even in London.

Steve Clifford is general director of the Evangelical Alliance, United Kingdom.