Musannaf Ibn Abi Shayba 9:1391

Abu Bakr narrated to us, he said: Abbad bin al-Awwam narrated to us, from Sakhr bin Juwayriyah, from Nafi, that Ibn Umar was asked about a woman who made her slave-girl lawful for her husband. Ibn Umar said: "I do not know. Perhaps if this had happened during the time of Umar, he would have stoned him. She is not lawful for you as a slave-girl, except as a slave-girl; if you wish, you may sell her, and if you wish, you may manumit her, and if you wish, you may gift her, and if you wish, you may marry her off to whomever you wish."