《资治通鉴·周纪·周纪二》
燕文公听从了苏秦的意见，给苏秦资助车马，去劝说赵肃侯。苏秦对赵肃侯说： 现在的时局，崤山以东的国家没有比赵国强盛的，最让秦国头疼的也是赵国。
文公从之，资苏秦车马，以说赵肃侯曰： 当今之时，山东之建国莫强于赵，秦之所害亦莫如赵。
 King Weng of Yan followed Su Qin's advice and provided Su Qin with a carriage and horses to persuade Zhao Suhou. Su Qin said to Zhao Suhou: In today's situation, no country east of Mount Xiao is stronger than the state of Zhao. The state of Qin is also most troubled by the state of Zhao.