《左传·襄公·襄公十年》
瑕禽说： 从前平王东迁，我们七姓人家跟随周天子，牺牲全都具备，天子信赖他们，而赐给他们用赤牛祭神的盟约，说： 世世代代不要失职 如果是柴门小户，他们能够来到东方而住下来吗？
瑕禽曰： 昔平王东迁，吾七姓从王，牲用备具。王赖之，而赐之骍旄之盟，曰： 世世无失职。 若筚门闺窦，其能来东底乎？
Xia Qin said: When King Ping moved east, we seven families followed King Zhou, and all the sacrifices are complete. The king trusted them and granted them a covenant to use red cows for sacrificing: Do not neglect your duties from generation to generation. If they were just ordinary families, would they be able to come east and settle down?