《史记·七十列传·刘敬叔孙通列传》
北边靠近匈奴敌寇，东边有六国的旧贵族，宗族势力很强，一旦有什么变故，陛下是不能高枕无忧的。
北近胡寇，东有六国之族，宗彊，一日有变，陛下亦未得高枕而卧也。
In the north, there are Xiongnu enemies, and in the east, there are the old nobles of the Six Kingdoms, whose clan power is very strong. Once there is any change, Your Majesty cannot rest easy.