《三国志·魏书·程郭董刘蒋刘传》
太祖将要征讨袁尚和辽西、上谷、右北平三郡的乌丸人，部下大多担心刘表会派刘备偷袭许县以征讨太祖，郭嘉说： 曹公虽然声威震动天下，但胡人仗着他们处在偏远之地，一定没有防备。
太祖将征袁尚及三郡乌丸，诸下多惧刘表使刘备袭许以讨太祖，嘉曰： 公虽威震天下，胡恃其远，必不设备。
The First Emperor was about to conquer Yuan Shang and Karasuma in the three counties of Liaoxi, Shanggu, and Youbeiping. Most of his subordinates were worried that Liu Biao would send Liu Bei to attack Xuchang secretly to punish him. The First Emperor, Guo Jia said: Although Cao Gong's prestige shocked the world, the Hu people thought that they were so powerful. In a remote place, there must be no precautions.