《资治通鉴·汉纪·汉纪五十六》
程畿说： 乐羊吃下他儿子的肉，并不是没有父子间的恩情。而是为了维护君臣大义。
畿曰： 乐羊食子，非无父子之恩，大义然也。
Cheng Ji said: When Le Yang ate the flesh of his son, it was not because he had no love for his son, but because he wanted to uphold the great principles of sovereign and subject.