Malik related to me from Nafi that Safiyya bint Abi Ubayd informed him that Umar ibn al-Khattab said, "What is the matter with men who have intercourse with their slave-girls and then leave them to go? No slave-girl comes to me whose master confesses that he has had intercourse with her but that I connect her child to him, whether or not he has practised coitus interruptus or left off from intercourse with her."