Sumayy reported that the Messenger of Allah ﷺ said, "On the Day of Resurrection, a great and heavy man will come who will not weigh with Allah as much as the wing of a mosquito." Then he said, "Recite, 'So We will not assign to them on the Day of Resurrection any weight'" [Kahf 18:105].
عن رسول الله ﷺ قال: إنه ليأتي الرجل العظيم السمين يوم القيامة، لا يزن عند الله جناح بعوضة وقال: اقرؤوا {فلا نقيم لهم يوم القيامة وزنا}
Bukhari narrated it in the Book of Tafsir (4729), and Muslim narrated it in the Book of the Description of the Day of Resurrection (2785), both through the route of Mughira bin Abdul-Rahman Hizami, who said, Abu Zinad narrated to me, from Araj, from Abu Hurairah, and he mentioned it.