Answer:
Thousands lay up gold within this house, But no man made it. Spears past counting guard this house, But no man wards it.
A man parks his car outside of a hotel and immediately realises he is bankrupt. How did it happen?
Plow and hoe, reap and sow, What soon does every farmer grow?
They're up near the sky, on something very tall. Sometimes they die, only then do they fall.
I build up castles. I tear down mountains. I make some men blind. I help others to see.
You use it between your head and your toes, the more it works the thinner it grows.