《新唐书·列传·卷四十四》
后来，白居易在殿中与穆宗谈论此事，论辩执著，坦率耿介，穆宗尚未谕，居易就对穆宗说： 陛下错了！ 
后对殿中，论执强鲠，帝未谕，辄进曰： 陛下误矣。 
Later, Bai Juyi talked about this matter with Emperor Muzong in the hall. His argument was persistent and frank. Emperor Muzong hadn't spoken yet, and Juyi said to Emperor Muzong: Your Majesty is wrong!