Sahih Muslim
The Book Giving Description of the Day of Judgement, Paradise and Hell (Kitab Sifat Al-Qiyamah wal Janna wan-Nar)
Book Number: 039 / Hadith Number: 6749
Mujahid said: (I have had the privilege) of accompanying Ibn 'Umar up to Medina but I did not hear him narrate anything from Allah's Messenger (may peace be upon him) except one hadith. And he said: We were in the presence of Allah's Messenger (may peace be upon him) that there was brought to him the kernel of a date. The rest of the hadith is the same.