Musnad Ahmad 1366

It was narrated that an-Nazzal bin Sabrah said: We prayed Zuhr with ‘Ali (رضي الله عنه), then he went to a gathering that he used to hold in ar-Rahbah. He sat and we sat around him, then the time for ‘Asr came. A vessel (of water) was brought to him. He took a handful from it and rinsed his mouth and nose, and he wiped his face and forearms, and he wiped his head, and he wiped his feet. Then he stood up and drank what was left over in the vessel. Then he said: I have been told that some men dislike anyone to drink whilst standing, but I saw the Messenger of Allah (ﷺ) do what I have done.