I love walking through a bike shop and “window shopping.” Never mind that I already own a road bike and an off-road bike. Never mind that I have nowhere to put another bike. Never mind that I have a family to care for. I enjoy the fantasy of owning something new.

On the one hand, this can be harmless fun—who doesn’t like to daydream about new stuff? But on the other hand, my desires can easily go too far, and I have to guard my heart against doing something unwise that could hurt my family and our relationships.

Jesus understands that sometimes we might be around an attractive person and feel tempted to “window shop.” When he speaks of lust in this passage, it’s more than just noticing someone—it’s a look or a fantasy with intent. It means treating a human being as an object we’d like to have.

In today’s world, that kind of fantasizing is called normal and is even encouraged. But Jesus explains that it violates God’s commands.

When we lust after another person, we violate them, ourselves, and our current or future marriage. We take a part of our heart that belongs to our spouse and give it to someone else. So Jesus warns us that we must avoid temptation and keep our hearts in line with his.