《周书·列传·卷二十五》
众人都不作声，没有一个说话。李远说： 立世子凭嫡生而不凭长幼，礼制上说得明明白白。
众皆默，未有言者,远曰： 夫立子以嫡不以长，礼经明义。
No one said a word. Li Yuan said: The crown prince should be the legitimate son, not just the eldest son. This is clearly laid out in the code of conduct.