日中则移,月满则亏,物盛则衰,天之常数也;进退、盈缩、变化,圣人之常道也。· It is the general order of Heaven that the sun will decline as soon as it reaches the meridian,that the moon is going to wane as soon as it waxes to full,and that things go down as soon as their zenith is reached. Accordingly,the Tao of sages normally considers advances and withdraws,expansion and contraction,and change and transformation.
(Strategies of the Warring States [475 BC-221 BC])