Abu Sa'id al-Khudri (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him); he (peace and blessings be upon him) said: "Whoever sees an evil, if he has the power, let him stop it with his hand; if he does not have the power, let him forbid it with his tongue; otherwise, let him hate it in his heart, and that is the weakest of faith."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب آداب القاضي / 20179