“Whoever looks at a woman to lust for her has already committed adultery” (Matthew 5:28). These are radical words and even kingdom citizens must struggle not to resist. Their severe probing of the heart brings pain as the Son of God touches the raw nerves of our moral diseases. Jesus, having dealt with the problem of hate and malice, now addresses the problem of lust. The Pharisees had certainly treated the issue of adultery, but only superficially. Their concern was to avoid a capital offense (Leviticus 20:10; Deuteronomy 22:22). One can almost hear the way they said, “You shall not commit adultery” (Exodus 20:14). Jesus, in contrast, tracks the sin of adultery to its lair (Matthew 15:19). As the hatred of the heart is murder, so is the unbridled lust of the heart adultery.
This principle was not an obscure part of the Mosaic covenant. The tenth commandment pointedly said, “You shall not covet your neighbor’s wife” (Exodus 20:17). Paul, while still a stranger to the gospel, and a Pharisee, had been severely penetrated by this command (Romans 7:7). Even Job, a man who apparently lived before the law, understood this ethical truth. “I have made a covenant with my eyes,” he said, “Why then should I look upon a young woman?” (Job 31:1).
Though some extended application might be made from this passage to the raw and unprincipled carnal desire which some single person might harbor for someone similarly unattached, Jesus’ use of the word “adultery” makes clear that His present concern is with that illicit desire which violates the very spirit of the marriage covenant (2 Corinthians 11:2-3). The Lord’s concern in this whole section is with our duty to love others. No married person can do justice to his mate while given over to unrestrained desire for another. Though yet a matter of the mind it is called what it is – sin.
The Lord is not dealing here with the mere momentary passing of desire through the mind; otherwise there would be no distinction between temptation and sin. (We should not be aghast at the suggestion that the lust of the flesh might have made its approach to the mind of our Savior while He remained sinless, Hebrews 4:15.) The words, “looks at a woman to lust for her,” help us to understand the exact nature of the transgression. This is not a fleeting thought but the gathering up of one’s mind for the purpose of lusting. The Greek text describes a person who directs his thoughts or turns his mind to a thing; in this case, lusting after a woman (or a man). Obviously, we do not look at everything we see. The eye takes in a vast panorama and it is left for the mind to focus the attention. David’s sin was not in seeing the unclothed Bathsheba but in looking upon her, setting his mind and ultimately his unbridled lust upon her (2 Samuel 11:2-5). David wanted the opportunity to possess Bathsheba, and found it. His violation of Exodus 20:17 would have been no less had that opportunity never presented itself.
Although the English word “lust” accurately connotes the sensual overtones of the Greek verb (epithumeo), it may lack the attendant thought of possession which is inherent in it (Guelich, The Sermon on the Mount, p. 194). The sin being described by Jesus is the calculated cultivation of the desire to possess one to whom you have no right. If this sin is to be escaped, the very first approach of such thoughts must be decisively rejected, before they can take possession of the mind and will. In the language of an old proverb: “You cannot keep the birds from flying over your head but you can keep them from building a nest in your hair.” If we find difficulty in distinguishing between the temptation and the sin in this case it is far wiser to err on the side of caution than on the side of recklessness.
The war of the kingdom citizen with lust in these times is destined to be severe and hard-fought. We are not going to easily escape the miasma of lasciviousness, fornication and adultery that has descended on this generation. Let no disciple be smug (1 Corinthians 10:12). There are no societal restraints to lean on. Our strength and defense must reside wholly in our own deep and unshakable resolve to keep ourselves pure for the Lord’s sake. In the final analysis that is where the issue of our faithfulness in the kingdom has always been decided. “Keep your heart with all diligence, for out of it spring the issues of life” (Proverbs 4:23).