"The Analects of Confucius Bashu" said: "Confucius said' Guan Ju', you are happy but not lewd, and you are sad but not hurt." In a word, both sadness and joy are "sentimental"; No sex and no harm means "stop at etiquette".
The same poetic theory and the same result, some people mistakenly think that this sentence comes from the Analects of Confucius.