Sahih Muslim
The Book Pertaining to Piety and Softening of Hearts (Kitab Al-Zuhd wa Al-Raqaiq)
Book Number: 042 / Hadith Number: 7101
Simak b. Barb reported: I heard Nu'man deliver an address in which he said that (Hadrat) Umar made a mention of what had fallen to the lot of people out of the material world and he said: I saw Allah's Messenger (may peace be upon him) spend the whole day being upset because of hunger and he could not get even an interior quality of dates with which he could fill his belly.