Musannaf Ibn Abi Shayba 1:2089

Muhammad ibn Bishr narrated to us, he said: Hushaym ibn Sa’d narrated to us, he said: Zayd ibn Aslam narrated to us, from ‘Amr ibn Sa’d al-Jari—and he was a freed slave of ‘Umar—he said: ‘Umar came to us returning from the Hajj among a group of the companions of the Messenger of Allah, may Allah bless him and grant him peace. He said: "O son of Sa’d, bring us napkins." So napkins were brought to him. He said: "Wash yourselves with them, for it is blessed."