It was narrated from Abu Buraidah from his father that:
An-Najashi gave the Prophet a gift of a pair of plain black leather socks. He put them on, then he (performed ablution and) wiped over them. (DE)
English reference (DE): Vol. 1, Book 1, Hadith 549 (DE)
Arabic reference (DE): Book 1, Hadith 592 (DE)