A test

I now travel, though controlling it is tricky.
I can stop death itself for any being, any illness, but none of the oh so wise humans will listen, for they know much better?
I imagine some times walking into a children's hospital and saving ever life, yet mans wisdom will not allow them to drink my water?
That is the key, just sip my water and eternity is yours, in plain english, but your wisdom will not allow you to so much as try...
This post in plain will be removed, but for now I want to test man wisdom?