《新唐书·列传·卷二十九》
李承乾的太子身份被废除，太宗了解实际情况，说道： 听说您多次劝谏，承乾不听您的，所以到了这个地步。 
太子败，帝知状，谓曰： 闻公数谏，承乾不听公，故至此。 
Li Chengqian's position as crown prince was abolished. Taizong understood the situation and said: I heard that you repeatedly remonstrated but Chengqian did not listen to you, so now he has reached this point.