《老子·德经·第五十五章》
认识淳和的道理叫做 常 ，知道 常 的叫做 明 。贪生纵欲就会遭殃，欲念主使精气就叫做逞强。
知和曰常，知常曰明，益生曰祥，心使气曰强。
To know the principle of harmony is called "chang", and to know "chang" is called "ming". Greed and indulgence will lead to disaster, and desire for energy is called "cheng qiang".