Musnad Ahmad 33:1018

Hassan ibn Musa and Surayj narrated to us, they said: Hammad ibn Zayd narrated to us, from Amr ibn Dinar, from Muhammad ibn Ali, from Jabir ibn Abdullah, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, forbade the meat of donkeys." Surayj said: "The domestic ones, on the day of Khaybar, and he permitted the meat of horses."