《三国志·魏书·荀彧攸贾诩传》
太祖常常称赞说： 公达表面上愚笨实际上胸怀谋略，表面上怯懦实际上勇武，表面上力弱实则刚强，不夸耀自己的长处，不炫耀自己的功劳，他的智谋别人能达到，但他表面上的愚陋别人是比不上的，就算是颜子、宁武也不能胜过他。 
太祖每称曰： 公达外愚内智，外怯内勇，外弱内强，不伐善，无施劳，智可及，愚不可及，虽颜子、甯武不能过也。 
The Grand Ancestor often praised him, saying: “On the surface, Gongda is thick-headed, but in reality, he is full of plans. On the surface, he is cowardly, but in reality, he is very brave. On the surface, he is weak, but in reality, he is very strong. He will not boast about his strength, and he will not flaunt his achievements. His intellect may be something that others can attain, but his superficial obtuseness is beyond the reach of others. Even someone like Yan Zi or Ning Wu could not surpass him.”