Intention vs. Behavior

Here is a thought that am currently pondering: which is more problematic, the idea of committing a sin or the actual commission of a sin? Jesus says in Matthew 5:27 & 28, "You have heard it said, 'Do not commit adultery.' But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart." While I completely believe that this scripture is valuable in its meaning and intention, I have a hard time believing that thinking it is equal to doing it. If this were literally the case, then each man on this planet is a raging, unbridled adulterer.

Take in to consideration a lesser sin. I have been around certain idiotic people in my time that I would love to poke squarely in the eyes and to whom I wish to cause serious retinal damage. Obviously I do not perform the actual behavior (at least never a time that can be proven beyond reasonable doubt). Certainly the absence of ocular mutilation is better than if my fingers were given their way.

Or consider this from an opposite angle. If I see a woman being raped and I think to myself, "I should go right over there and beat the face off that guy," and then turn around and continue walking, could I justly say that my intentions were pure? I have known many who have been confronted with wrongs and immediately jump to the defense that "its all a matter of the heart." I doubt the raped woman would find solace in that load of philosophical poop-fest.

I will probably revisit this issue again. In the meantime, I would love comments and responses.