Musannaf Ibn Abi Shaybah

Hazrat Dharr narrates that I went to Safwan bin Assal Muradi. He asked, "Why have you come?" I replied, "In search of knowledge." He said, "The angels spread their wings under the feet of the seeker of knowledge." Then he said, "When we were on a journey, the Messenger of Allah (peace and blessings be upon him) would instruct us not to remove our leather socks for three days except in the state of major impurity (janabah), even if we had relieved ourselves or slept."