《旧唐书·列传·卷十三》
太宗又说： 武德六年以后，太上皇有废除建成立我为太子的想法又拿不定主意，在这期间，我不被建成、元吉宽容，确实产生了功劳丰伟而得不到奖赏的忧虑。
太宗又曰： 武德六年以后，太上皇有废立之心而不之定也，我当此日，不为兄弟所容，实有功高不赏之惧。
Taizong said again: "After the sixth year of Wude, the Supreme Emperor had the idea of abolishing Jiancheng and making me the crown prince, but he couldn't make up his mind. During this period, I was not tolerant of Jiancheng and Yuanji, and I did have the worry of having great merit without getting a reward.