Musnad Abu Ya'la al-Mawsili 150:33

Ishaq narrated to us, Waki' narrated to us, from Ibn Abi Dhi'b, from Makhlad ibn Khufaf, from 'Urwah, from 'Aishah, who said: The Messenger of Allah (may Allah bless him and grant him peace) decreed that the yield (kharaj) is in return for the liability (daman).