One thing that occurs to me is that an "entitlement" becomes a "right", to some extent, as resources increase.
So for example, if we were an ancient tribe and food was scarce, people would just have to fend for themselves. I can't be expected to give up my food to feed others when I am having a hard time feeding myself.
But as resources improve, the situation changes. It's not unreasonable to ask people to give up their dream of owning TWO cars, settling for just the one, in order to make sure no one goes hungry. This is a mild form of redistributing wealth which no remotely compassionate person disagrees with.
Given the vast potential resources of modern society, I think it's legitimate to expand food to things like shelter, health care, education, and suchlike. Precisely how much wealth should be redistributed before it becomes unfair is tough to say.....
It's interesting to read Thomas Paine's criterion in his essay 'Agrarian Justice'. His criterion for redistributing wealth is basically this: first, he observes that what is called civilized society results in classes of people who are much happier and wealthier, and some who are much more miserable than the people who make up so-called 'primitive' nomads living off the land, in complete freedom, in man's "natural" state. The advanced technologies of Britain during the industrial revolution did not prevent a mass of workers from leading disgusting, miserable lives far worse than the lives of Native Americans, say. Britain was extremely wealthy yet many British were impoverished. (One might say analogous things about iPhones and SUV's with eleven cupholders today....)
Anyway, Paine's criterion for the redistribution of wealth for the poor, then, is it should be just enough to ensure that conditions for everyone in a 'civil' society are no worse than what people would have if they abolished civil society and lived as primitives in their natural state. Makes sense to me.
I think we can extend Paine's reasoning to reach a more general criterion.
One might say that as society's change and evolve over time, they become more "civil" if you like (more technology, more organization) and acquire more wealth and resources. The broad criterion for distributing wealth for the poor would then be this: Wealth should be distributed enough so that conditions for everyone are no worse than what they would be if they reverted to a *less* civil, less wealthy society.