A violent wind does not outlast the morning; a squall of rain does not outlast the day. Such is the course of Nature. And if Nature herself cannot sustain her efforts long, how much less can man!
When a country is in harmony with the Tao, the factories make trucks and tractors. When a country goes counter to the Tao, warheads are stockpiled outside the cities. There is no greater illusion than fear, no greater wrong than preparing to defend yourself, no greater misfortune than having an enemy. Whoever can see through all fear will always be safe.
Seal the openings, shut the doors, and until your last day you will not be exhausted. Widen the openings, interfere, and until your last day you will not be safe.
He who knows much about others may be learned, but he who understands himself is more intelligent. He who controls others may be powerful, but he who has mastered himself is mightier still.