He who is in harmony with the Tao
is like a newborn child.
Its bones are soft, its muscles are weak,
but its grip is powerful.
It doesn't know about the union
of male and female,
yet its penis can stand erect,
so intense is its vital power.
It can scream its head off all day,
yet it never becomes hoarse,
so complete is its harmony.
Translation of the Tao Te Ching by Stephen Mitchell
