《资治通鉴·汉纪·汉纪九》
总之，不能因为喜欢汉朝使臣的甜言蜜语，就进京去朝见天子，您真的去了，就不能返回来了，这是亡国的情势啊！ 
要之，不可以说好语入见，则不得复归，亡国之势也。 
In short, you should not go to the capital to pay homage to the emperor because you like the sweet words of the Han envoy. If you really did, you will not be able to come back. This is a situation of national ruin!