《韩非子·说林下》
晋平公对秦景公说： 看在晋国面子上放出楚王的弟弟，我就不再筑城了。 
谓秦公曰： 为我出荆王之弟，吾不城也。 
Duke Ping of Jin said to Duke Jing of Qin: For the sake of Jin, release the younger brother of the king of Chu, and I shall not build the city.