《资治通鉴·晋纪·晋纪三十二》
赵思说： 狗马都还知道留恋主人，我赵思虽然是一个受了宫刑的人臣，但还是想请求您允许我回去追随皇上。 
思曰： 犬马犹知恋主，思虽刑臣，乞还就上。 
Zhaoshu said: Even dogs and horses still know to stay with their masters. Although I, Zhaoshu, am a subject who has suffered castration, I still wish to ask you to allow me to return to follow the Emperor.