Hadith on Munkar: Whoever sees evil should change it if possible

Abu Sa’id al-Khudri reported: The Messenger of Allah, peace and blessings be upon him, said, “Whoever among you sees evil, let him change it with his hand. If he is unable to do so, then with his tongue. If he is unable to do so, then with his heart, and that is the weakest level of faith.”

Source: Ṣaḥīḥ Muslim 49

Grade: Sahih (authentic) according to Muslim

عَنْ أَبِي سَعِيدٍ الْخُدْرِيّ رَضِيَ اللهُ عَنْهُ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَنْ رَأَى مِنْكُمْ مُنْكَرًا فَلْيُغَيِّرْهُ بِيَدِهِ فَإِنْ لَمْ يَسْتَطِعْ فَبِلِسَانِهِ فَإِنْ لَمْ يَسْتَطِعْ فَبِقَلْبِهِ وَذَلِكَ أَضْعَفُ الْإِيمَانِ

49 صحيح مسلم كتاب الإيمان باب بيان أن النهي عن المنكر من الإيمان والأن الإيمان يزيد وينقص