A skillful commander is not overbearing. A skillful fighter does not become angry. A skillful conqueror does not compete with people. One who is skillful in using men puts himself below them. This is called the strength to use men. This is called matching Heaven, The highest principle of old.
LaoziClay is fashioned into vessels; it is on their empty hollowness that their use depends. Doors and windows are cut out to make a dwelling, and on the empty space within, its use depends. Thus, while the existence of things may be good, it is the non-existence in them that makes them serviceable.
Laozi