When you see a mirror and it shows you dirt on your face, you won't be angry at the mirror. Rather you will thankfully receive the information given by the mirror. You will go to the washroom and clean your face. This hadith gives a great piece of advice. A believer is sometimes a mirror and at other times, sees himself in the mirror. In collective life, we are sometimes the mirror and at other times we see ourselves in the mirror. Both roles have been mentioned. The role is to look into the mirror without any reaction, without being offended.
A saying is mentioned in many books of Hadith with minor difference in wording. Two of these are: الْمُؤْمِنُ مِرْآةُ الْمُؤْمِنِ (Sunan Abi Dawood 4918) and الْمُؤْمِنُ مَرْآةُ أَخِيهِ (Al-Adab al-Mufrad 238) Both have the same meaning: A believer is a mirror to another believer. The example of the mirror is very meaningful. One is the mirror and the other is the one who looks into the mirror. The first believer is a mirror, and the second sees himself in the mirror. The role of the mirror is that it shows you things as they are. If you see your face in the mirror, it will show you what you really are. It would nothing less nor more. The believer who becomes a mirror to you, or gives you advice, must be very objective. He must not understate nor exaggerate. He must say what truly is the matter. This truthfulness is necessary to be well-wisher.
A believer should be a sincere well-wisher for another believer. And not only for a believer, but also for every human being. When he offers an advice, he must be objective. He must speak honestly. This is the role of the mirror. The other role is of the one who sees or hears. When you see a mirror and it shows you dirt on your face, you won't be angry at the mirror. Rather you will thankfully receive the information given by the mirror. You will go to the washroom and clean your face. This hadith gives a great piece of advice. A believer is sometimes a mirror and at other times, sees himself in the mirror. In collective life, we are sometimes the mirror and at other times we see ourselves in the mirror. Both roles have been mentioned. The role is to look into the mirror without any reaction, without being offended. If the mirror shows you some dirt, you won't get offended. You won't feel bad. Similarly, if your brother gives you advice, points out a mistake, then you must not get offended. When you don’t get offended at what the mirror tells you, you must not get offended at the advice someone gives you.