Musannaf Ibn Abi Shayba 13:1646

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Jarir ibn Hazim narrated to us, he said: A man asked Salim ibn ‘Abd Allah, he said: "My father has an *umm walad* (a slave woman who bore him a child) who committed adultery; should I sell her?" He said: "No, her adultery is upon herself, and she is a free woman."