Musnad Ahmad 944:19

'Abd al-Rahman ibn Mahdi and Muhammad ibn Ja'far narrated to us, they said: Shu'bah narrated to us, from al-Hakam and Hammad, from Ibrahim, from Abu 'Abd Allah al-Jadali, from Khuzaymah ibn Thabit, from the Prophet, peace and blessings of Allah be upon him, regarding wiping over the leather socks (khuffayn). He said: "For the traveler, three days and their nights, and for the resident, a day and a night."