4. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from Ali ibn al-Hakam from al-‘Ala’ ibn Razin from Muhammad ibn Muslim who has said the following: “I once asked abu Ja’far عليه السلام, about the case of a man if he could marry the filthy (prostitute). He (the Imam) said, ‘No, he cannot do so.’ He (the Imam) said, ‘If he has a slave-girl with whom he has gone to bed but she must not be taken as the mother of his children.’” (He must use contraceptives)