Understanding others is knowledge, Understanding oneself is enlightenment; Conquering others is power, Conquering oneself is strength.
LaoziA vessel is formed from a lump of clay with care, however, it is the empty space within the vessel that makes it useful.
LaoziThe reason why rivers and seas are able to be lords over a hundred mountain streams, is that they know how to keep below them. That is why they are able to reign over all the mountain streams.
Laozi