1. The Master said: Is not the Book of Changes supreme? By means of it the holy sages exalted their natures and extended their field of action.
Wisdom exalts. The mores make humble. The exalted imitate heaven. The humble follow the example of the earth.
These words are explicitly attributed to Confucius, consequently the essay of which they are a part cannot in its entirety have originated with Confucius, but is rather a product of his school. Actually the several chapters do contain commentaries of very different sorts, which probably also belong to different periods.
We are shown here how the Book of Changes, correctly used, leads to harmony with the ultimate principles of the universe. The sages exalt their natures by acquiring the wisdom preserved in this book, and thus they arrive at harmony with heaven, which is high. On the one hand, the mind gains loftiness of viewpoint; on the other hand, the field of action is widened. This comprehensiveness gives rise to the idea of mores: the individual subordinates himself to the whole. Through such humble subordination, the sages arrive at harmony with the earth, which is low. Thus the individual enlarges his field of action.
2. Heaven and earth determine the scene, and the changes take effect within it. The perfected nature of man, sustaining itself and enduring, is the gateway of the tao and of justice.
Heaven is the scene of the spiritual, earth is the scene of the corporeal. In these worlds move the things that develop and are transformed according to the rules of the Book of Changes. So likewise the nature of man, which is perfected and endures, is the gateway through which the actions of man go in and out, and when man is in harmony with the teachings of the Book of Changes, these actions correspond with the tao of the universe and with justice. Tao, which manifests itself as kindness, corresponds with the light principle, and justice corresponds with the dark principle: the one relates to the exalting and the other to the broadening of man's nature.