《后汉书·列传·文苑列传下》
从前周公旦的父亲是文王，哥哥是武王，九命作伯，以治理华夏，还一饭三吐饣甫，一沐三握发，接见匹夫，所以周道因之隆高，天下的人都归德于周。
不图遭疾，幽闭莫启。昔周公旦父文兄武，九命作伯，以尹华夏，犹挥沐吐餐，垂接白屋，故周道以隆，天下归德。
In the past, the father of Duke of Zhou was King Wen, and his brother was King Wu. He was an Earl with nine appointments, and was in charge of the Central Plains. He even spat out food three times a meal, and washed his hair three times before meeting ordinary people, so the morals of the Zhou Dynasty flourished, and the people of the world all turned to the Zhou Dynasty.