《资治通鉴·隋纪·隋纪七》
李密挑选军中特别骁勇的士兵八千人，分别隶属于四骠骑作为自已的侍卫队，号称 内军 。他常说： 这八千人足以抵挡百万人。 
选军中尤骁勇者八千人，分隶四骠骑以自卫，号曰内军，常曰： 此八千人足当百万。 
Li Mi selected 8,000 uncommonly brave soldiers from the army, who were under the command of the four cavalry generals as his personal guards. They were called "Inner Army". He often said: "These 8,000 men are enough to stop a million men."