《宋史·列传·卷一百一十七》
如果派遣能言善辩之士暂时和金人谈判什么能行什么不能行及其理由，住留几天，等勤王的大军从四面八方聚集，他金军孤军深入，虽然得不到所要求的，也将迅速离去。
若遣辩士姑与之议所以可不可者，宿留数日，大兵四集，彼孤军深入，虽不得所欲，亦将速归。
If we send someone who can speak well and argue with the Jurchen people for a while, what can and cannot be done, and the reasons for it, stay for a few days, and wait for the army of King Qin to gather from all directions. Although he, the Jurchen army, went deep into the country, even if he could not get what he asked for, he would leave quickly.