《汉书·传·韦贤传》
特别严重的时候，匈奴出动十余万军队，逼近京城驻扎，围困四周边境；朝廷每年发兵防备匈奴，匈奴危害中原由来已久，不是一代形成的。
甚者，兴师十余万众，近屯京师及四边，岁发屯备虏，其为患久矣，非一世之渐也。
At times of particular seriousness, the Huns would send out hundreds of thousands of troops to approach the capital to station themselves and to lay siege to surrounding borders. The court sent troops every year to defend against the Huns. There was a long-standing reason why the Huns' harm to the Central Plains was not formed in one generation.