Sunan Ibn Majah, Chapter: The Chapters on Divorce

"A man came to the Prophet (saw) and said: 'O Messenger of Allah, my master married me to his slave woman, and now he wants to separate me and her.' The Messenger of Allah (saw) ascended the pulpit and said: 'O people, what is the matter with one of you who marries his slave to his slave woman, then wants to separate them? Divorce belongs to the one who takes hold of the calf (i.e., her husband).’ “