It is narrated from Sayyiduna Awf bin Malik al-Ashja'i (may Allah be pleased with him) that during the Battle of Tabuk the Messenger of Allah (peace and blessings be upon him) ordered "wiping over leather socks for three days and three nights for the traveller, and a day and a night for the resident."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1306