It is narrated from Abu Hurairah, may Allah be pleased with him, that the Messenger of Allah, peace and blessings be upon him, said: "Do you know what backbiting is?" The noble companions, may Allah be pleased with them, said, "Allah and His Messenger know best." He, peace and blessings be upon him, said: "It is your mentioning about your brother something which he dislikes." It was asked, "O Messenger of Allah, tell me, if what I say is actually present in my brother?" He, peace and blessings be upon him, said: "If what you say is in him, then you have backbitten him, and if what you say is not in him, then you have slandered him." In another narration: "When you say something about your brother which is in him, then you have backbitten him, and when you say something which is not in him, then you have slandered him." Narrated by Muslim.