Musannaf Ibn Abi Shayba 1:1918

Ibn Fudayl narrated to us, from Bayan, from Qays, from a man—Bayan said: I think he is one of the companions of the Prophet (may Allah bless him and grant him peace)—who said: "If I were to feel uneasy about wiping over the leather socks, I would have felt uneasy about praying in them."