This isn't really a parable. I just found out that parables tend to have human characters. Sorry about the inaccurate post-tile but I do love this story and wanted to share.
Do you know the difference between the Dead Sea and the very much alive Sea of Galilee? The Dead Sea has no outlet. Both are fed by the same source but the Dead Sea can only receive an inward flow. The Dead Sea is prevented from flowing outward and the accumulation of salt has killed it. The Sea of Galilee is alive only because what flows in can also flow out.
-From The Story Factor, Annette Simmons