Book 6: 《雍也》 Yong Ye (There is Yong)
《雍也》 Passage 6.29
子曰：「中庸之為德也，其至矣乎！民鮮久矣。」
Legge Translation (1861)
The Master said: "Perfect is the virtue which is according to the Constant Mean! Rare for a long time has been its practice among the people."