Commands: purity in thought and desire.
Forbids: unchaste or impure thoughts, desires of another's wife or husband, and all other unlawful impure thoughts and desires.
I, for one do not think that thought should get you to hell. I always thought that as long as you didn't act on desires then you were good to go but now I can't even think about doing bad things. Well then what is the point of a conscious I ask you. Why even have a moral dilemma if the very thought of having a dilemma is wrong in the first place. This is basically saying that you should always think good things no matter what. How many of us have crushes on actors or singers that are married or in a relationship? Now, that's wrong? Jesus, what are we allowed to do then.
I can't control my mind constantly, sometimes it wonders off into the dark side and I let it play a while so that I can live out a fantasy that is wrong without actually doing the actions. Isn't it best that we only think certain things instead of doing them. Come on God, sometimes you have to choose the lesser evil and I think in this case there is a clear winner. I would much rather have someone think about having sex with my loved one instead of actually trying to do it. If anything, we should be glad that we can have those kinds of thoughts because if we didn't god knows what would happen.
I'm sure there would be a lot more shit going down. A lot more adultery, theft, murder. I know I watch bank heist movies and think, "Well if I robbed a bank and took a million bucks that wouldn't be so bad." I'm not actually going to rob a bank but I guess even thinking about doing so is enough to send me the other way into flames. I would get into a lot of arguments and car accidents if I constantly had to control my mind. Imagine how focused you would be all the time, but not on important stuff. I'm sure the rate of unemployment would sky rocket. Who could focus on accounting or banking if they're telling themselves not to think about banging the receptionist.
If anything, it is by the grace of god that we have the ability to think before we act and freedom of choice is something that god wanted for us. If there was no fantasy or pre-thought than there would be no freedom of choice because the only choice would be the right one. If I was God I would be happy with an impure thought rather than an impure action. I think it shows humanity in control. In a time when control is lacking and all we have is the power to think before we do something, that is something to be proud of. So instead of making this a sin, this should be a bonus point into heaven. For every impure thought you have and don't act on you get a gold star and you are that much closer to the pearly gates, Yes, I think that is much more reasonable.