《史记·七十列传·张耳陈馀列传》
以原来一个赵国的力量就能轻而易举地攻下燕国，何况两位贤王相互支持，以杀害赵王的罪名来讨伐，灭亡燕国就更容易了。 
夫以一赵尚易燕，况以两贤王左提右挈，而责杀王之罪，灭燕易矣。 
With the power of the original Zhao Kingdom, it was easy to conquer the Yan Kingdom. What's more, with the support of the two virtuous kings, it was even easier to destroy the Yan Kingdom in the name of killing King Zhao.