It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A huge, fat man will come on the Day of Resurrection who will not weigh (even) as much as the wing of a mosquito." Then he (peace and blessings be upon him) said: "Recite (this verse if you wish): 'So We will not assign to them any weight on the Day of Resurrection.'"
No one other than Mughirah bin Abd al-Rahman narrated this hadith from Abu al-Zinad, and Sa'id bin Abi Maryam is alone in narrating it from him.
Hadith Referenceالمعجم الأوسط / باب الألف / 192
Hadith Takhrij«أخرجه البخاري فى «صحيحه» برقم: 4729، ومسلم فى «صحيحه» برقم: 2785، والبزار فى «مسنده» برقم: 8173»