河間獻王曰：「湯稱學聖王之道者，譬如日焉，靜居獨思，譬如火焉，夫捨學聖王之道，若捨日之光，何乃獨思，若火之明也？
可以見小耳，未可用大知。
惟學問可以廣明德慧也。」
Prince Xian of Hejian said, “When Tang praised the study of the way of the sage-kings, he compared such study to the sun and compared solitary meditation to a fire.