Mukhtasar Muslim (Abridged) 902 — If an owner beats his slave, he

It is narrated from Sayyiduna Suwaid bin Muqarrin (may Allah be pleased with him) that when a man slapped his slave-girl, Sayyiduna Suwaid (may Allah be pleased with him) said, "Do you not know that hitting the face is forbidden? And look at me: in the blessed time of the Messenger of Allah (peace and blessings of Allah be upon him), we seven brothers had only one servant. One of my brothers slapped her, so the Messenger of Allah (peace and blessings of Allah be upon him) ordered her to be set free."