《后汉书·列传·荀韩钟陈列传》
《汉纪》的序言说 ：从前，圣人创建帝王治国的准则，经纬天地，观察自然以立法，于是创造文字，以通宇宙，传播于王庭，用处大得很啊。
其序之曰：昔在上圣，惟建皇极，经纬天地，观象立法，乃作书契，以通宇宙，扬于王庭，厥用大焉。
The preface to "Han 紀" says: In the past, the saints established the principles of imperial rule, the latitude and longitude of the world, and observed nature to make laws. Therefore, they created writing to communicate with the universe and spread it in the royal court. Its uses were very great.