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 cannot do so, then with his tongue. If he cannot do so, then with his heart, which is the weakest level of faith.”
Source: Ṣaḥīḥ Muslim 49
Grade: Sahih (authentic) according to Muslim
عَنْ أَبِي سَعِيدٍ الْخُدْرِيّ 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