这封信是马援率兵远征期间写给两个侄儿的书信。在信中，马援针对两个侄子喜欢议论别人，爱结交轻薄侠客的弱点，以自己平生的经验指导他们如何为人处世。马援（前14—后49）字文渊，东汉扶风茂陵（今陕西兴平东北）人。新莽时，为新城大尹。后依附隗嚣，继归刘秀，攻灭隗嚣，为陇西太守。官至伏波将军，封新息侯。后在进击武陵"五溪蛮”时，病死军中。著有《铜马相法》。
《马援戒兄子严敦书》
援兄子严、敦，并喜讥议，而通轻侠客。援前在交趾，还书诫之曰：
吾欲汝曹闻人过失，如闻父母之名：耳可得闻，口不可得言也。好论议人长短，妄是非正法，此吾所大恶也；宁死，不愿闻子孙有此行也。汝曹知吾恶之甚矣，所以复言者，施衿结，申父母之戒，欲使汝曹不忘之耳！
龙伯高敦厚周慎，口无择言，谦约节俭，廉公有威。吾爱之重之，愿汝曹效之。杜季良豪侠好义，忧人之忧，乐人之乐，清浊无所失。父丧致客，数郡毕至。吾爱之重之，不愿汝曹效也。效伯高不得，犹为谨敕之士，所谓刻鹄不成，尚类 者也。效季良不得，陷为天下轻薄子，所谓画虎不成，反类狗者也。讫今季良尚未可知，郡将下车辄切齿，州郡以为言，吾常为寒心，是以不愿子孙效也。
Ma Yuan's Letter to His Nephews, Yen and Jun
Mr. Ma Yuan had two nephews who were fond of making fun of others and also criticizing other. He liked to be with the smart set. So Mr. Ma wrote them a letter exhorting them to be more serious. The following is his letter.
When you hear of others' faults, I hope you will feel as if you heard the names of your parents: you may listen, but you may not mention them. I dislike people given to criticizing others' conduct and the law of the country. I would rather die than hear of your doing this. You very well know of my intense hatred of such criticism. Here I have mentioned it again because I wanted you to remember it, just as parents often give their last word of advice to their daughter on her wedding-day.
Lung Paik-kao is honest and careful. He does not speak evil of others. He is modest, economical, incorruptible, and upright, and commands respect. I love him and look up to him and hope that will imitate him. Tu Chi-liang is a chivalrous man. He is sad when he finds somebody else sad, and happy when he finds somebody else happy. He keeps company with both good and bad men. People of several countries came to attend his father's funeral. I love him and look up to him. But I do not want you to imitate him. For if you fail in imitating Pai-kao you can still be an honest student. It is like carving the figure of a swan: if it does not look like a swan, people may take it to be at least a wild-duck. Then, if you fail in imitating Chi-liang, you will become a scapegrace. It is like painting a dog. I do not yet know what will become of Chi-liang. Whenever a new governor of his country assumes office, he usually speaks of him as an enemy. I am always afraid lest he should get into trouble. That is why I hope that you will not imitate him.
