Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrates: We were with the Prophet (peace and blessings be upon him) when a man submitted: "O Messenger of Allah! How incapable so-and-so is!" (The narrator is unsure; perhaps the words were:) "How weak so-and-so is!" The Prophet (peace and blessings be upon him) said: "You have backbitten your companion and you have eaten his flesh."
This narration was recorded by Imam Abu Ya'la and by Imam al-Tabarani in al-Mu'jam al-Awsat, and their wording is: "A man got up and left the presence of the Prophet (peace and blessings be upon him), and the people saw incapacity in the way he rose, so they said: 'How incapable so-and-so is!' The Prophet (peace and blessings be upon him) said: 'You have eaten your brother and you have backbitten him.'" The chains of both narrations contain a narrator, Muhammad bin Abi Humayd, who according to one view is called Hammad, and he is extremely da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأدب / 13144
Hadith Gradingمحدثین:ضعیف جداً
Hadith Takhrij«اخرجه أبو يعلى فى المسند (6151) أخرجه الطبراني فى المعجم الاوسط (461) ، أخرجه المعجم الأوسط للطبراني برقم: 461، وأخرجه إتحاف الخيرة المهرة بزوائد المسانيد العشرة برقم: 5366/3»