Musannaf Ibn Abi Shayba 19:832

Abu Bakr narrated to us, he said: Abbad bin al-Awwam narrated to us, from Umar bin Amir, from Hammad, from Ibrahim: That Ali and Abdullah differed regarding an *umm walad* (a slave woman who has borne a child to her master) who committed adultery. Ali said: "She is to be flogged, and she is not to be banished." And Abdullah said: "She is to be flogged and she is to be banished."