In which my toddler makes me question the foundation of my ethical stance on economic charity

[Judah opens up his mini-kitchen cupboard where he stashes his hoard of fake and real coins.]

Judah: I have lots of money Mommy.  I'm rich!

Spouse: Do you want to share some with us?

Judah: Sure!  Then I won't be rich anymore.

*pause*

Judah: Mommy, I can be rich.  Or I can be generous.

Me--floored.  From the mouth of babes--what profound and interesting insight.  Even if one doesn't agree, you gotta admit that's a pretty heavy concept to wrestle with.

I can be rich.  Or I can be generous.

If you're rich and have more than enough, what is your obligation to your fellow man?
What does it mean to be generous?
How much do you need to share?
Should you share until the point where you're no longer rich?

[Note: I'm not advocating a political view, but rather asking about one's own private moral and ethical inclinations.  Please don't think I'm a commie.]