Musnad Ahmad 27:789

Waki’ narrated to us, from al-‘Umari, from Nafi’, from Ibn ‘Umar, that he performed *ramal* (brisk walking) from the Black Stone to the Black Stone for three [circuits], and walked for four, and prayed two rak’ahs at the Station [of Ibrahim]. Then he mentioned that the Prophet, peace and blessings of Allah be upon him, did that.