Musnad Abu Ya'la al-Mawsili 2:84

Ishaq narrated to us, Hajjaj narrated to us, from Shu'bah ibn al-Hajjaj, from Simak ibn Harb, that he heard al-Nu'man ibn Bashir delivering a sermon. He said: Umar ibn al-Khattab mentioned what the people had attained of worldly goods, and he said: "I saw the Messenger of Allah (peace and blessings of Allah be upon him) spending the day twisting [in hunger], not finding even the poorest quality of dates to fill his stomach."