What does this mean?
Does this mean EVERY man who looks at a women with Lust is committing adultery?
Even if they’re both single?
What does this mean?
Jesus here perfects the old law, which makes no mention of the acts of the mind and will. It constitutes a call to perfection, that we strive for Godliness with our minds and hearts as well as our deeds. If we do not commit adultery, and yet secretly lust after women, we commit adultery in our hearts. We can observe the reality of that statement today when a wife discovers her husband is looking at pornography. The pain of betrayal is tangible in the many threads posted here on the subject.
TO quickly try to add to that as best I can - A sinful thought does not mean something that pops into your head that we have no control over unless the person purposely decides to entertain and enjoy it.
Sort answer is “Yes”.
Something that needs to be remembered is that in ancient times there weren’t a lot of men and women “singles” around. The vast majority were betrothed at what we sould see as a very early age.
So - if you looked lustfully at another woman you were basically looking at a woman promised to another…Women/Girls not promised in marriage were usually consecrated virgins to the temple…So they too were “betrothed”, in this case to God.
If that is what it says then that is what it means.
By definition, adultery occurs between married persons. To look lustfully upon a single person is tantamount to committing fornication in your heart. Why? Because since you do not even know that person or their heart, there is no love involved, but only lust. Thus, you desire their body for the sake of your own pleasure. That fact that this other person may be willing in their heart to indulge your fantasy, or even a physical act, does not mitigate the sinfulness of the matter one bit. It remains lust, without love, or a Sacramental bond between the two of you.
The Church has always considered fornication (sexual activity between singles) and adultery (sexual activity where at least one person is married, betrothed, or romantically bound to another). JKRH makes a good point about how most people in Jesus’ time were bound to another person in a more-than-friends way.
However, just because sexual activity between singles is not technically adultery, doesn’t make it right. Jesus’ point was that looking at someone in lust is misusing their body. A person who does that cares only about the physical features of the other person, not their soul. That doesn’t mean it’s wrong to find someone attractive, but it is wrong to treat their body like an object for pleasure and pleasuring. It is the person that should be important. Jesus even says that using “the legalities of marriage as a cover for lust is adultery”. Why would it be adultery to get married before having sex? Because in this case, the main reason the couple are getting married is to have sex (to satisfy their lust), rather than because they want to knit their souls together, in which case sexual desire for their partner is just an added bonus.