Al-Hasan (may Allah have mercy on him) said regarding the words of Allah Almighty, "And whoever among you does not have the means" [Surah an-Nisa: 25], "whoever among you is unable to marry", and "from your believing slave girls" [Surah an-Nisa: 25]: We have not been given permission regarding the slave women of the People of the Book.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14013