The greatness of heaven lies in yin and yang. Yang is virtue and Yin is punishment; Punishment leads to killing while morality leads to transformation.

Dong Zhongshu said: "The law of the movement of heaven lies in Yin and Yang. Yang is the rule of virtue, and Yin is the punishment. Punishment advocates killing, while rule by virtue advocates making people live. Therefore, Yang often stays in hot summer and takes bearing, nourishing and growing as his own responsibility. Yin often stays in the dead of winter, but lives in an empty and uninhabited place. This shows that God values morality, not punishment.