《吕氏春秋·纪·季春纪》
流动的水不会腐恶发臭，转动的门轴不会生虫朽烂，这是由于不断运动的缘故。
流水不腐，户枢不蠹，动也。
Running water does not become stagnant or putrid, and revolving door-hinges do not become wormy or rotten, because they are in constant movement.