http://revach.net/article.php?id=3821

Section: Tzedaka   Category: Lessons in Tzedoka
Like Sheep Speeding Through The Water
The gemara says (Gittin 7a) if a person see his wealth shrinking he should make from them tzedaka, and certainly if his wealth is great.  The pasuk says, "V'Chein Nagozu V'Avar", and then he will cut and pass (Nachum 1).  D'Bei Rebbi Yishmael explains this with a Mashal.  If a person has two sheep that must cross the river, one is full with wool and the other is bare, the bald sheep will pass the water and make it to the other side while the one with the wool will sink and drown.

Wealth, says the gemara, will weigh you down, but if you "shear" your wealth you will fly past Gehinom.  This applies to both the rich and poor alike.  The Likutei Basar Likutei brings from the Ein Eliyahu who explains that this is quite a significant promise since like wool which is shorn only to let more grow back again, the wealthy man who give tzedaka for the purpose of further bracha from Hashem.  Nevertheless he will be spared Gehinom.  

The poor man who gave tzedaka to escape his miserable plight will also be spared Gehinom even though he traded his Gehinom on earth for richer pastures by investing in Tzedaka.  Whatever troubles he deserved in this world and escaped from, through his giving, will not come back to haunt him in the next world.

The lesson here is that no matter what condition your finances are in, Tzedaka defies gravity and is the world's only "no risk" deal.  It is a great investment both in this world and in the next.