《淮南子·修务训》
这是因为天下出现以强凌弱、以多欺少、以诈骗愚、以勇侵怯、满腹经伦不肯指导别人、积财满堂不肯给济别人的现象，所以才拥立帝王来使天下团结平等；又因为天子帝王的聪明才智不足以普及遍照天下海内，所以又设置三公、九卿来辅佐帝王天子；还因为遥远异邦、偏僻地区无法承受到帝王天子的德泽，所以又分封诸侯来教诲那里的民众。
为天下强掩弱，众暴寡，诈欺愚，勇侵怯，怀知而不以相教，积财而不以相分，故立天子以齐一之。为一人聪明而不足以遍照海内，故立三公九卿以辅翼之。绝国殊俗，僻远幽闲之处，不能被德承泽，故立诸侯以教诲之。
As we see injustice, oppression, deceit, and encroachment in the world and disdain and indifference for the less fortunate and the less knowledgeable as well, we should elect emperors to bring equality and unity to the world; and as no emperor shall be wise and capable enough to rule the vast world, we should appoint the Three Dukes and Nine Ministers to assist the emperor; and since remote and distant areas could not get the benefits of the emperor's enlightenment, we should establish dukes to teach people in the far ends of the realm.