2- عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ حَمَّادٍ عَنِ الْحَلَبِيِّ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ تَزَوَّجِ الْحُرَّةَ عَلَى الأمَةِ وَلا تَزَوَّجِ الأمَةَ عَلَى الْحُرَّةِ وَمَنْ تَزَوَّجَ أَمَةً عَلَى حُرَّةٍ فَنِكَاحُهُ بَاطِلٌ.
2. Ali ibn Ibrahim has narrated from his father from Ibn Abi ‘Umayr from Hammad from al-Halabiy who has said the following: “Abu ’Abd Allah 
, has said, ‘A free woman can become a second wife, the first wife being a slave-girl; but a slave-girl cannot become a second wife, the first wife being a free woman. If one marries a slave-girl as a second wife, the first being a free woman, such marriage is invalid.’”
