Principles of Enjoining Good and Forbidding Evil

Whoever of you sees something evil, let him change it with his hand; and if he is not able, then with his tongue; and if he is not able, then with his heart, and that is the weakest of faith

Abu Sa‘īd al-Khudri (may Allah be pleased with him) reported: I heard the Messenger of Allah (may Allah's peace and blessings be upon him) say: "Whoever of you sees something evil, let him change it with his hand; and if he is not able, then with his tongue; and if he is not able, then with his heart, and that is the weakest of faith."