《周礼·天官冢宰·大宰》
用九种和协的办法联系天下各国的百姓。第一是诸侯国君，以土地取得百姓。
以九两系邦国之民：一曰牧，以地得民。
Use nine harmonious methods to connect the people of all countries in the world. The first is the feudal lord, who obtains the people with land.