Musnad Ahmad 27:2009

Hammad ibn Khalid narrated to us, from Abdullah, from Nafi’, from Ibn Umar, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, made a contract with the people of Khaybar for half [of the produce]. He used to give his wives from it one hundred wasqs: eighty of dates and twenty of barley." Abu Abd al-Rahman said: "I read these hadiths to my father until the end of them."