Zirr bin Hubaysh (may Allah have mercy on him) says: I came to Sayyiduna Safwan bin Assal al-Muradi (may Allah be pleased with him), and he asked: "What has brought you?" I said: "I have come in search of knowledge." He said: "We used to say that the angels spread their wings for the seeker of knowledge out of pleasure with what he seeks." Then I asked him about wiping over the leather socks. He said: "When we were on a journey with the Messenger of Allah (peace and blessings be upon him), we would wipe for three days and nights, and the resident would wipe for a day and a night."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7337