Musnad Ahmad 27:1928

'Abd al-Razzaq narrated to us, Ma'mar informed us, from Ayyub, from Nafi', from Ibn 'Umar, who said: "The Prophet, peace and blessings of Allah be upon him, used to go out on the day of Fitr with an 'anzah (a short spear), and he would plant it in front of him, and he would pray facing it."