《资治通鉴·唐纪·唐纪三十三》
李光弼派人向郭子仪求救，郭子仪率兵出井陉关，夏季，四月壬辰，到了常山，与李光弼合兵，共有蕃汉步、骑兵十余万。
光弼遣使告急于郭子仪，子仪引兵自井陉出，夏，四月，壬辰，至常山，与光弼合，蕃、汉步骑共十馀万。
Li Guangbi sent someone to ask Guo Ziyi for help. Guo Ziyi led his troops out of Jingxing Pass, and in the summer, on Renchen in April, reached Changshan and joined forces with Li Guangbi, having more than a hundred thousand infantry and cavalry of various ethnicities.
<s>[INST] Identify the key themes in this Classical Chinese text and explain them in English: 光弼遣使告急于郭子仪，子仪引兵自井陉出，夏，四月，壬辰，至常山，与光弼合，蕃、汉步骑共十馀万。 [/INST] Li Guangbi sent someone to ask Guo Ziyi for help. Guo Ziyi led his troops out of Jingxing Pass, and in the summer, on Renchen in April, reached Changshan and joined forces with Li Guangbi, having more than a hundred thousand infantry and cavalry of various ethnicities.</s>
Identify the key themes in this Classical Chinese text and explain them in English: 光弼遣使告急于郭子仪，子仪引兵自井陉出，夏，四月，壬辰，至常山，与光弼合，蕃、汉步骑共十馀万。
user
Li Guangbi sent someone to ask Guo Ziyi for help. Guo Ziyi led his troops out of Jingxing Pass, and in the summer, on Renchen in April, reached Changshan and joined forces with Li Guangbi, having more than a hundred thousand infantry and cavalry of various ethnicities.
assistant