Yahya related to me from Malik that Nafi and Abdullah ibn Dinartold him that Abdullah ibn Umar arrived at Kufa and went to Sad ibnAbi Waqqas, who was the Amir of Kufa at that time. Abdullah ibn Umarsaw him wiping over his leather socks and disapproved of it. So Sadsaid to him, "Ask your father when you get back." Abdullah returnedbut forgot to ask Umar about the matter until Sad arrived and said,"Have you asked your father?" and he said, "No."Abdullahthen asked Umar and Umar replied, "If your feet are ritually pure whenyou put them in the leather socks then you can wipe over the socks."Abdullah said ,"What about if we have just come from relievingourselves?" Umar said, "Yes, even if you have just come from relievingyourself."
USC-MSA web (English) reference: Book 2, Hadith 43
Arabic reference: Book 2, Hadith 73