Musnad Ahmad 27:410

Yazid ibn Harun narrated to us, Shu'bah informed us, from Khubayb ibn 'Abd al-Rahman ibn Khubayb, from Hafs ibn 'Asim, from Ibn 'Umar, who said: "I prayed with the Prophet, peace and blessings of Allah be upon him, and Abu Bakr, and 'Umar, and 'Uthman for six years at Mina, and they performed the prayer of the traveler."