《资治通鉴·汉纪·汉纪六十》
曹操告诫曹彰： 在家的时候，我们是父子；接受任务后，就变成了君臣，一举一动都要按朝廷法令行事，你要小心！ 
操戒彰曰： 居家为父子，受事为君臣，动以王法从事，尔其戒之！ 
Cao Cao warned Cao Zhang: At home, we are father and son; after you receive an assignment, we are sovereign and subject. You must act in accordance with the imperial laws in everything you do. Be careful!