It compared punishment and rewards with yin and yang ( negative and positive principles). It believed the Dao of Heaven to be the basis for punishment and rewards and pointed out punishment and rewards were indispensable means of rule by law. 它把刑、德与阴、阳联系起来,把天道作为使用刑、德的依据,指出刑、德是实行法治不可或缺的两种手段。