Er is a Chinese character, meaning vice; It is also the capital form of "two", which is used for counting and accounting; Also refers to defection and betrayal. This passage is recorded in Zhou Li Naijiuzheng and Book of Rites Quli. Common phrases: Chen Er, Er Xin, Bu Er Guo, Er Jie, Bu Er, Er Ling, Er Gu, Zuo Er, Duan Er, Wu Er, Guo Nai Er, Er Gong, Yi Er, Lu Li Er Duan.

The Book of Rites is introduced as follows:

Dai Sheng, a etiquette scholar in the Western Han Dynasty, compiled various etiquette works written by Confucius disciples from the Warring States Period to the early Han Dynasty, as well as their re-biography and three biographies, and called them Xiao or Xiao Dai. There are 20 volumes and 49 articles.

The Book of Rites mainly records the pre-Qin ritual system, and embodies the pre-Qin Confucian philosophical thoughts (such as the view of heaven, world outlook and outlook on life) and educational thoughts, such as personal cultivation, education system, teaching methods and school management.

Political thoughts (such as civilizing politics, building a harmonious society, and making criminal laws by rites) and aesthetic thoughts (such as touching theory and harmony of rites and music) are important materials for studying the pre-Qin society, and they are also a compilation of Confucian thoughts. The Book of Rites is a social change after the Warring States and the Western Han Dynasty, including the inheritance and change of social system, etiquette system and people's ideas. It is one of the classic works of Confucianism.

Its ideas include social, political, ethical, philosophical, religious and other aspects, among which "University", "The Doctrine of the Mean" and "Book of Rites" contain rich philosophical thoughts. At the end of the Eastern Han Dynasty, Zheng Xuan, a famous scholar, made an excellent interpretation of The Book of Rites of Little Dai. Later, this book became popular, and gradually became a classic from the works explaining the scriptures.

As follows:

The Book of Rites was compiled by Dade, a ritual musician in the Western Han Dynasty, and his nephew Dai Sheng. Eighty-five pieces of Selected Works of Great Virtue were called "Dai Dai Li Ji", but in the later circulation process, only thirty-nine pieces were left in the Tang Dynasty. Dai Shengxuan's forty-nine articles are the Book of Rites of Little Dai that we see today.

These two books have their own emphases and choices, and each has its own characteristics. At the end of the Eastern Han Dynasty, Zheng Xuan, a famous scholar, made an excellent interpretation of The Book of Rites of Little Dai. Later, this book became popular, and gradually became a classic from the works explaining scriptures. It is listed as one of the "Nine Classics" in the Tang Dynasty and one of the "Thirteen Classics" in the Song Dynasty, and it is a must-read book for scholars.