If one is going to preach this parable as a story about social justice (which is a perfectly acceptable reading of the text) the first thing one must do is answer the question, "What is the rich man's sin?"
Let me go ahead and say that it absolutely cannot be the fact that he is wealthy. I know that this will get preached in enough mainline protestant churches this weekend to give it some credibility, but it just isn't true. And when the wealthy members of those churches get mad and start looking for a new place to worship, please let them know St. Paul's in Foley would love to get to know them.
Nowhere in the parable does Jesus say the man's wealth sent him to Hades. He does say that during his lifetime the rich man had received his good things, but honestly that could be said about a lot of people, rich or not. Instead, the rich man's sin is the chasm he dug between himself and Lazarus.
I am being very intentional in making it sound like the rich man made a very active effort to separate himself from Lazarus, which I fell comfortable saying because in the scene with Father Abraham, the rich man knows Lazarus' name. "Father Abraham, have mercy on me, and send Lazarus to dip the tip of his finger in water and cool my tongue; for I am in agony in these flames."
His sin was not one of simple omission; ignoring the man at his gate while he lived lavishly. Instead, the rich man very intentionally dug a ditch between himself and a crippled beggar named Lazarus. And so, when the rich man died, the ditch that he had dug himself became a fixed chasm that could not be crossed.
The rich man got what he wanted, a life separate from the ugliness and sadness of the poor and needy, and he got it for all of eternity. The question this text raises for me then is the opposite side of the "rich man's sin" question, "what do I want?" Odd are, I'm going to get what I want, but maybe for a lot longer than I ever intended.