Right.......but, "adultery in the heart" is the result of lusting (the absence of God's love).
Where do you get your definition of lust as 'the absense of God's love'? The Greek word refers to longing or desire, and in the New Testament, it is used consistently in a negative sense. The word in Matthew 5:28 is a grammatically appropriate form of epithumeo, which you can look up with the Strong's Concordance code G1937.
I've got a copy of e-Sword with the Septuigint on it, with words coded to Strong's numbers. Aside from the fact that the find function isn't working, it's pretty cool to have.
It is interesting to see that Exodus 20:17 uses this same Greek word coded G1937, the grammatically appropriate form of the epithumeo.
17 “You shall not covet your neighbor’s house. You shall not covet your neighbor’s wife, or his male or female servant, his ox or donkey, or anything that belongs to your neighbor.”
The word for 'covet' over and over again is that same Greek word from Matthew 5:27 (in the grammatically appropriate form).
The question is, can you covet what is your own? Exodus 20:17 forbids coveting your neighbor's wife. You don't covet your own wife, or house, or donkey, or ox, or servant. If you covet, you covet what belongs to someone else. If a house is yours, it is not wrong for you to want to go home and sleep there. It's yours. You should give thanks to God for it. If a man desires his wife sexually, that's okay, because it is his wife.
Notice Matthew 5:27 does not say that desiring a woman is adultery, but looking to desire her is adultery. Like Romans 6 teaches, we should nto yeild are members as instruments of unrighteousness unto sin. There is an act of the willin choosing to look with lust here. It's not something uncontrollable. It is not mere attraction.
But I say to you that everyone who looks at a woman with lustful intent [wishing to use her, for his own personal satisfaction---with the absence of genuine love] has already committed adultery with her in his heart [he's been unfaithful and is loving pleasure more than God].~ Jesus (in Matthew 5:27-28)
It seems you are making up your own definitions here (or borrowing someone else's made up definitions.) I don't see the connection with what the words mean through a word study.
Something else to keep in mind is that Jesus was commenting on the law. He actually quoted a verse that he was commenting on here.
Matthew 5
27 “You have heard that it was said to those of old, ‘You shall not commit adultery.’ 28 But I say to you that whoever looks at a woman to lust for her has already committed adultery with her in his heart.
This is commentary on the command not to commit adultery. Physical adultery involved sex with someone who was not your own spouse. Jesus talks about how a heart can be contaminated with adultery. But it is grounded concretely with this verse, directly related to the concept of real, physical adultery.
When we consider the use of the term 'lust', we need to consider it's usage in terms of how it is used in scripture. The Septuigint was the Greek translation used in the first century. The word used for 'lust' here is used in the command not to covet, and the command indicates that what is not to be coveted are possessions or wives that belong to someone else, not one's own. It's not coveting to have sexual desire for one's own wife.
Also, look at some of the other things Jesus said in the passage. Several verses earlier, he quoted the law "Do not murder" and warned against angrily calling your brother names like 'raca' and 'thou fool.' Notice that anger here has a relationship to murder. There is some kind of semantic connection between the two concepts. He isn't calling all evil speaking murder. He isn't calling swearing oaths murder and not keeping them murder. He quotes the verse about murder, and then warns against speaking these angry kinds of words. This is commentary on the law. Not only should we not perform the actions, but we shouldn't harbor the same attitudes in our hearts that lead to the sins forbidden in the Torah. So we shouldn't murder, but we shouldn't have anger and hatred in our hearts toward our brother or express them with our mouths. We shouldn't commit adultery, but neither should we have adultery in our hearts by yeilding our eyes to look with coveteousness upon a woman.
Doesn't this make more sense?
1. It sticks closely with the way the word translated 'lust' is used in the Old Testament.
2. The commands of Jesus about adultery and murder are tightly connected to his teachings against having sin in the heart.
3. The word 'adultery' does not need to be redefined loosely so as to have little or no connection to what the word literally means.