Chinese Folk Poem: "The Human Route"

Much wisdom is lost because it is obscure or difficult. Often worse, it may be ambiguous or even apparently self-contradictory, not a condition favored in today's certainty-driven world. Contrarian thinking may be the only salvation when confronted with such wisdom, if any thinking at all will work.

Below is a poem I came across recently which entranced me (provenance uncertain). Its statements and questions got my blood going, the questions especially. But the last question is the big one. Who will take a stab at that gem, and what wisdom lieth therein?

Coming empty-handed, going empty-handed, that is human.
When you were born, where did you come from?
When you die, where do you go?
Life is like a floating cloud, which appears.
Death is like a floating cloud, which disappears.
The floating cloud itself originally does not exist.
Life and death, coming and going, are also like that.
But there is one thing that always remains clear.
It is pure and clear,
Not depending on life and death.

Then what is the one and clear thing?