《周礼·秋官司寇·衔枚氏&司仪》
用九种礼仪区别诸侯、诸臣的爵命等级，以统一各诸侯国的礼仪，而用以接待诸侯国的宾客。
以九仪辨诸侯之命，等诸臣爵，以同邦国之礼，而待其宾客。
The king used nine types of rituals to differentiate the ranks of feudal lords and feudal ministers, to unify the rituals of feudal states, and to receive guests from feudal states.