"‏ مَنْ رَأَى مُنْكَرًا فَاسْتَطَاعَ أَنْ يُغَيِّرَهُ بِيَدِهِ فَلْيُغَيِّرْهُ بِيَدِهِ فَإِنْ لَمْ يَسْتَطِعْ فَبِلِسَانِهِ فَإِنْ لَمْ يَسْتَطِعْ فَبِقَلْبِهِ وَذَلِكَ أَضْعَفُ الإِيمَانِ ‏"

Marwan brought out the pulpit on 'Id. He began preaching before the prayer. A man stood and said: You opposed the sunnah, O Marwan. You brought out the pulpit on the 'Id, it was not brought out before: and you began preaching before the prayer. Abu Sa'id al-Khudri said: Wh is this (man) ? They (people) said: So-and so son of so-and-so. He has performed his duty. I heard the Messenger of Allah (ﷺ) say: He who observes and evil deed should change it with his hand if he can do so; if he cannot do, (he should change it) then with his tongue; if he cannot do then (he should change it) with his heart, and that is the weakest degree of the faith.