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