Musnad Ahmad 27:2004

Hammad ibn Khalid narrated to us, Abdullah narrated to us, from Nafi’, from Ibn Umar, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) designated al-Naqi’ as a protected pasture (hima) for horses." I said to him, "O Abu Abd al-Rahman"—meaning al-Umari—"his horses?" He replied, "The horses of the Muslims."