《资治通鉴·汉纪·汉纪四十七》
陈国少年魏昭向郭泰请求说： 教授经书的老师容易遇到，但传授做人道理的老师却难遇到。我愿意跟随在您的身边，给您洒扫房屋和庭院。 
陈国童子魏昭请于泰曰： 经师易遇，人师难遭，愿在左右，供给洒扫。 
Wei Zhao, a young man from the state of Chen, asked Guo Tai: Teachers who teach scriptures are easy to find, but teachers who teach the principles of life are hard to find. I am willing to follow you and sweep the floor and yard for you.