Musnad Ahmad 511:1

Waki’ narrated to us, Isma’il narrated to us, from Qays, from Dukayn ibn Sa’id al-Khath’ami, who said: We came to the Messenger of Allah, may Allah bless him and grant him peace, and we were four hundred and forty men, asking him for food. The Prophet, may Allah bless him and grant him peace, said to ‘Umar: "Stand up and give them." ‘Umar said: "O Messenger of Allah, I have nothing except what sustains me and the children for the summer season (qayz)." Waki’ said: "The qayz in the speech of the Arabs is four months." He said: "Stand up and give them." ‘Umar said: "O Messenger of Allah, I hear and I obey." He said: So ‘Umar stood up and we stood with him. He ascended with us to a room of his, took the key from his waist-wrapper, and opened the door. Dukayn said: And behold, in the room was a pile of dates similar to a crouching young camel. He said: "Take what you need." He said: So every man among us took his need, as much as he wished. He said: Then I turned around, and I was among the last of them, and it was as if we had not diminished a single date from it.