Yahya related to me from Malik from Nafi that Abdullah ibn Umarsaid, "If a man gives his slave permission to marry, the divorce is inthe hand of the slave, and nobody else has any power over his divorce.Nothing is held against a man who takes the slave-girl of his maleslave or the slave-girl of his female-slave."
USC-MSA web (English) reference: Book 29, Hadith 51
Arabic reference: Book 29, Hadith 1211