Musannaf Ibn Abi Shayba 13:2289

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Shu’bah narrated to us, from Muhammad ibn Jahadah, from Abu Hazim, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) forbade the earnings of a slave girl.