Because prophecies could herald a state's foundation or its destruction, rulers from the Han onwards were keenly aware that they were a force which could mobilize the people to rebel. Thus dynasties down the ages strictly prohibited ordinary people from keeping written prophecies, calling them "demonic words."
由於讖語能開國也能傾國，漢朝以後的當政者深知它是民間動員造反的力量，因此歷代都對讖文嚴加查禁，稱之「妖言」，不許民間私藏。