《资治通鉴·唐纪·唐纪三十五》
这时颜真卿从河北到达，说： 曹将军冒着生命危险要去传达皇上的命令，为何要阻拦他呢！
会颜真卿自河北至，曰： 曹将军不顾万死，以致帝命，何为沮之！
At this time, Yan Zhenqing arrived from Hebei and said, "General Cao is willing to risk his life to deliver the imperial order, why would you try to stop him!"