廣弘明集 8.33

8.33

Originating in qi, form, and substance, yet not separated from one another, it is called primordial chaos. Looking, it cannot be seen; listening, it cannot be heard; tracking, it cannot be grasped: thus it is called the Changes. The Explication of the Classic of Filial Piety says: 'The odd is the joint of yang; the even is the base of yin. Attaining yang, it is completed; joining with yin, it dwells. Numbers mating with each other constitutes the Way.' Therefore it is said: 'One yin and one yang is called the Way; that which yin and yang cannot measure is called the spiritual.' Looking from afar at this, it is well worthy of being esteemed over Laozi.