Musnad Ahmad 33:672

Abu Ja'far al-Mada'ini Muhammad ibn Ja'far narrated to us, Warqa' informed us, from Muhammad ibn al-Munkadir, from Jabir ibn Abdullah, who said: I was with the Messenger of Allah, peace and blessings of Allah be upon him, on a journey, and we reached a watering place. He said, "Will you not go down to the water, O Jabir?" I said, "Yes." He said: So the Messenger of Allah, peace and blessings of Allah be upon him, descended, and I went down to the water. Then he went to relieve himself, and I placed water for his ablution. He came and performed ablution, then stood and prayed in a single garment, having crossed its two ends over his shoulders. I stood behind him, and he took hold of my ear and placed me on his right side.