《汉书·传·魏相丙吉传》
这个驭吏是边郡的人，熟知边塞报警警备等事。曾有一次出去，刚巧看见驿骑拿着赤白相间的信囊，是边郡报告敌人入侵的书信来了。
此驭吏边郡人，习知边塞发奔命警备事，尝出，适见驿骑持赤白囊，边郡发奔命书驰来至。
This coachman was from a border region, and he was familiar with border alarms and precautions. Once, when he was out, he happened to see a courier holding a yellow and white satchel, which was a letter from the border region reporting that the enemy had invaded.