Sufyan bin Uyaynah narrated to us; he said: Sufyan al-Thawri said to me: "Do you have anything of food (provision)?" I said: No, nothing. He said: Then afterwards I mentioned a hadith; Ma'mar narrated it to us from al-Zuhri, from Malik, from Umar (may Allah be pleased with him), that "the Prophet (peace and blessings be upon him) used to sell the dates of Banu al-Nadir and would keep back for his family their provision for a year."
Al-Bukhari (may Allah have mercy on him) narrated it in the Sahih from Muhammad bin Salam, from Waki'.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النفقات / 15700
It is reported from Sayyiduna Umar bin al-Khattab (may Allah be pleased with him), concerning the wealth that Allah granted to His Messenger as fay', that he said: "The Messenger of Allah (peace and blessings be upon him) would spend from this wealth on his family their maintenance for the year, then whatever remained he would place in the public treasury (bayt al-mal)."
Al-Bukhari narrated it in his Sahih from Ibn Bukayr and others, and Muslim recorded it from the hadith of Ma'mar and others.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النفقات / 15701