《淮南子·览冥训》
是因为他们达到了虚静无为纯粹专一的境界，而不是忙于琐碎的政事。
何则？至虚无纯一，而不喋苛事也。
Because they reached the realm of emptiness, tranquility, inaction, and concentration, instead of being occupied with trivial matters of government.