Sahih Bukhari, Chapter: Prayers (Salat)

Once I was traveling with the Prophet and he said, "O Mughira! take this container of water." I took it and Allah's Apostle went far away till he disappeared. He answered the call of nature and was wearing a Syrian cloak. He tried to take out his hands from its sleeve but it was very tight so he took out his hands from under it. I poured water and he performed ablution like that for prayers and passed his wet hands over his Khuff (leather socks) and then prayed.