The Messenger of Allah ﷺ said, "Each of you is the mirror of his brother, so if he sees something harmful in him, let him remove it."
حدثني أحمد بن محمد أخبرنا عبد الله بن المبارك أخبرنا يحيى بن عبيد الله عن أبيه
قال رسول الله ﷺ إن أحدكم مرآة أخيه فإن رأى به أذى فليمطه عنه
No references are available.
[Its chain of transmission is very daif] Baghawi narrated it in Sharh al-Sunnah, 13/92, Sharh al-Sunnah 13/92, no. 3513, from the hadith of Ibn Mubarak via this route, and it is also in his book Zuhd, p. 254, no. 730.Yahya bin Ubaydullah is matruk (abandoned), and Hakim went to an extreme and accused him of fabrication (Taqrib).What suffices in its place is the hadith of Abu Dawud, no. 4918, "The believer is the mirror of the believer, and the believer is the brother of the believer. He guards his interests for him and protects him from behind." Its chain is hasan, and Iraqi graded it hasan. On this subject there is also a hadith from Anas [Tabarani in Awsat, 3/21, no. 2135].