《左传·襄公·襄公九年》
秦景公派遣士雃向楚国请求出兵，准备进攻晋国，楚共王答应了。子囊说： 不行。
秦景公使士雃乞师于楚，将以伐晋，楚子许之。子囊曰： 不可。
Duke Jing of Qin sent Shi Lü to the State of Chu to request troops, preparing to attack the State of Jin. King Gong of Chu agreed. Zi Sang said: It won't do.