《资治通鉴·晋纪·晋纪十八》
再者，君王的军队在路途上需要五十多天，先驱者还没到达，消息已经传播很久了，敌贼的邮驿，以一日千里的速度传递消息，那么黄河以北的骑兵，就完全可以赶来救援。
又，王师在路五十馀日，前驱未至，声息久闻，贼之邮驿，一日千里，河北之骑，足以来赴。
Furthermore, the sovereign's army will take more than fifty days to travel on the road. The vanguard has not yet arrived, but the news has already spread for a long time. The enemy's postal service delivers news at a speed of a thousand miles a day, so the cavalry north of the Yellow River can come to the rescue in full force.