It was narrated from Hamzah bin Al-Mughirah bin Shu'bah that his father said:
"The Messenger of Allah (ﷺ) stayed behind, and I stayed with him. When he had relieved himself he said: 'Do you have any water with you?' I brought some water to him, and he washed his hands and face, then he started trying to uncover his arms, but the sleeves of his Jubbah were too tight, so he threw it over his shoulders and washed his arms and wiped over his forehead and 'Imamah, and over his Khuff."
Arabic/English book reference: Vol. 1, Book 1, Hadith 108