《旧唐书·列传·卷四十二》
魏元忠对李孝逸说 ：朝廷因您是王室懿亲，所以委以这平定叛乱的大事，天下的安危，实在要靠这一次决战。
元忠谓孝逸曰： 朝廷以公王室懿亲，故委以阃外之事，天下安危，实资一决。
Wei Yuanzhong said to Li Xiao: "The imperial court appointed you as the grand marshal to quell the rebellion because you are a noble relative of the royal family. The safety of the country really depends on this battle."