Musnad Ahmad 249:1

'Abd al-Samad ibn 'Abd al-Warith narrated to us, he said: My father narrated to me, Dawud—meaning Ibn Abi Hind—narrated to us, from Abu Harb, that Talhah narrated to him—and he was one of the companions of the Messenger of Allah (peace and blessings of Allah be upon him)—he said: I came to Medina and I had no acquaintance there, so I stayed in the Suffah with a man. Between me and him, there was a mudd of dates every day. One day, the Messenger of Allah (peace and blessings of Allah be upon him) prayed, and when he finished, a man from the companions of the Suffah said: "O Messenger of Allah, the dates have burned our stomachs, and our garments have become tattered." The Messenger of Allah (peace and blessings of Allah be upon him) ascended [the minbar] and delivered a sermon, then said: "By Allah, if I had found bread or meat, I would have fed it to you. However, you are soon going to reach [a time of prosperity], and whoever among you reaches that, large bowls will be brought to you in the evening, and you will wear [garments] like the coverings of the Ka'bah." He said: My companion and I remained for eighteen days and nights, having no food except *al-barir* (the fruit of the Arak tree), until we came to our brothers among the Ansar and they comforted us, and the best of what we obtained was these dates.