《礼记·中庸》
按官爵排列次序，就可以分辨出贵贱，按职位排列次序，就能分辨出贤与不贤；敬酒时晚辈先向长辈举杯，这样祖先的恩惠就会延及到晚辈，宴饮时按头发的黑白次序坐，这样就使老少有次序。
序爵，所以辨贵贱也。序事，所以辨贤也。旅酬下为上，所以逮贱也。燕毛，所以序齿也。
According to the ranks of officials, we can distinguish the noble and the humble; according to the order of position, we can distinguish the worthy and the unworthy; when toasting, the younger generation toasts the elder generation first, so that the favor of ancestors will be extended to the younger generation. When drinking, sit in order of black and white hair, so as to make the old and the young have an order.