Musnad Abu Ya'la al-Mawsili 42:175

'Amr al-Naqid narrated to us, Abu Ahmad al-Zubayri narrated to us, Sufyan narrated to us, from 'Uthman al-Batti, from Abu al-Khalil, from Abu Sa'id al-Khudri, who said: We captured female captives on the day of Awtas who had husbands, so we disliked having intercourse with them. We asked the Prophet, peace and blessings of Allah be upon him, and so [the verse] was revealed: "And [also prohibited are] women already married, except those your right hands possess" (An-Nisa: 24). So we deemed them lawful.