It is narrated from Hudhaifah (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: "By Him in Whose hand is my soul! You must certainly enjoin good and forbid evil, otherwise it is near that Allah will send His punishment upon you, then you will supplicate to Him but He will not accept your supplications." Hasan, narrated by Tirmidhi.