Temptation becomes an evil desire (e.g., adultery in the heart) when we look at a person for the purpose of lusting. Recognizing the aesthetic beauty of a person is not an evil desire—even if that person is not a spouse. Yet the moment that this recognition births evil desire in the heart by looking with lustful intent, it is sin.
In John Owen’s well-known work on sin and temptation, he defines two kinds of temptation: ones that come from without and others that come from within (Works, 6:194). The first kind of temptation works like this. I am hungry. And someone offers me stolen food. This temptation comes from without and is morally neutral.
The second kind of temptation works like this. From within me, I propose a desire to steal food for the pleasure of eating. According to Owen, “the very proposal from within, it being the soul’s own act, is its sin” (Works, 6:194).
Although this taxonomy of temptation may seem overly detailed, it becomes important when we ask the question: when does temptation become sinful? Or more specifically, when does sexual or romantic desire become sinful?
Married and Tempted
Here is what I mean. A married woman rightly can desire her spouse romantically and sexually. But what if she recognizes another man as an attractive man? Since polygamy is unnatural, does this recognition of beauty constitute sin? Has she experienced “evil desire” (Col 3:5)?
I answer no. In Matthew 5:28, Jesus defines when desire for someone becomes sin. He explains, “When someone looks at a woman for the purpose of lusting after her (pros to epithumesai auten), he has already committed adultery in his heart.”
Note two items. First, seeing a woman and recognizing the aesthetic appeal of that woman is itself not wrong. Jesus specifies that looking with lustful intent is wrong. The Greek construction pros to epithumesai auten signifies purposeful intent.
Second, the sinful act occurs “in his heart.” A desire that arises in our heart arises from within our fallen nature. This desire itself is sinful, or in the language of Paul is an “evil desire” (Col 3:5).
While Jesus gives a general principle, we can apply it to a married person. If the woman in the above example, sees a man whom she considers attractive, she does so without sin—if she does not look with lustful intent.