Musnad Ahmad 5:748

Bahz narrated to us, Shu'bah narrated to us, from 'Abd al-Malik ibn Maysarah, who said: I heard an-Nazzal ibn Sabrah say: I saw 'Ali, may Allah be pleased with him, pray the Dhuhr prayer, then he sat for the needs of the people. When the time for 'Asr arrived, a vessel of water was brought to him. He took a handful from it and wiped his face, his forearms, his head, and his feet. Then he took the remainder and drank while standing. He said: "Indeed, some people dislike this, but I have seen the Messenger of Allah, may Allah bless him and grant him peace, do it." And this is the ablution of one who has not broken his state of purity.