The wrong kind of desire in our lives can kill us according to this proverb. It is the desire of the sluggard that puts him to death. That seems strange because my first take on this would be that it is the lack of desire that would be his demise.
The word for desire here is the Hebrew word "ta-awah" and it means to crave greedily. It indicates something that is attractive to the eyes - and therefore is desirable to the person who sees it. In the second verse of our proverb we are told that all day long the sluggard is craving. The literal here is that he is "desiring desire." So what is going on here that is so dangerous for the sluggard? The second word used for "craving" here means to be coveting - to strongly desire something that someone else has. Thus, we see from both verses that the sluggard is filled with a desire and a covetous craving for things.
What kills the sluggard is that he is content with desiring and craving. He has plenty of desires, he just does not do anything to actually fulfill them. Consumed with desire, lust, and greed - he "craves" himself to death. Let's look at this a little closer.
We read first in verse 25 that the sluggard refuses to work. This one is a dreamer - but not a worker. In fact he refuses to work or give hismelf to the kind of labor that would eventually cause him to prosper and succeed. When he "refuses to work" there is a rebellioin present in his refusal. This word was used of Pharaoh's rebelliousness toward God in refusing to let Israel go. Thus this is an outright rejection of work. And as he refuses to work - he begins coveting what others have who do work. His desires continue to grow - even while he does nothing to solve his situation. In the end his own desires are his demise. He is consumed with longing and with desire for things - but will never attain them. He sits in his chair longing - ever longing - but never doing. Thus he dies of intense desire and want - but will never lift a finger to get the things he desires.
We are told at the end of this proverb that the righteous has a fundamentally different way of living than the sluggard. The righteous gives and does not hold back his generosity. He is not one ever filled with longing - but with a desire to bless others. The wicked, slothful man holds back his desire to give - because he wants all he has for himself. The strange thing is he has nothing because he won't work for it. The righteous works hard for what he has - and yet does not allow desire to kill him. He is looking for ways to give to others - to bless others - and to invest in others. He will not only know physical life - but he will also know spiritual life too. He will be a life-giving rather than just a stuff-wanting force on earth. He will not hold back his desire to bless others - and will be overjoyed and fulfilled again and again as he does.