It was narrated that Tariq bin Shihab said:
Abu Sa'eed Al-Khudri said: 'I heard the Messenger of Allah [SAW] say: Whoever among you sees an evil and changes it with his hand, then he has done his duty. Whoever is unable to do that, but changes it with his tongue, then he has done his duty. Whoever is unable to do that, but changes it with his heart, then he has done his duty, and that is the weakest of Faith.'