Musnad Ahmad 5:17

Hassan and Abu Sa’id, the freed slave of Banu Hashim, narrated to us, saying: Ibn Lahi’ah narrated to us, Abdullah ibn Hubayrah narrated to us, from Abdullah ibn Zurayr, that he said: I entered upon Ali ibn Abi Talib—Hassan said: on the day of Adha—and he brought near to us *khazirah* (a dish made of meat and flour). I said: "May Allah set you right, if only you had brought near to us some of this duck"—meaning the goose—"for Allah, the Mighty and Majestic, has increased the good." He said: "O son of Zurayr, I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: 'It is not lawful for the Caliph from the wealth of Allah except two bowls: a bowl that he and his family eat from, and a bowl that he places before the people.'"