Musnad Ahmad 141:1

'Affan narrated to us, Yahya bin Sa'id narrated to us, from Abu Ja'far al-Khatmi, who said: 'Umarah bin Khuzaymah and al-Harith bin Fudayl narrated to us, from 'Abd al-Rahman bin Abi Qurad, who said: "I went out with the Prophet, peace and blessings of Allah be upon him, for Hajj. I saw him come out from relieving himself, so I followed him with a water skin—or a cup—and I sat for him on the path. And he, when he would go to relieve himself, would go far away."