《旧唐书·列传·卷一百四十》
孔祯说： 恩宠是不能依赖的，大王不奉行国法，恐怕今日的荣誉地位，不是大王所能保住的，难道没看到淮南王刘长的事吗？ 
祯曰： 恩宠不可恃，大王不奉行国命，恐今之荣位，非大王所保，独不见淮南之事乎？ 
Kong Zheng said: Favour cannot be relied on, if the King does not follow the national laws, I'm afraid that the honour and status today, is not something that the King can keep, haven't you seen what happened to Liu Chang, the King of Huainan?