Al-Kāfi
Hadith 13435- أَحْمَدُ عَنْ أَبِيهِ عَنْ عَلِيِّ بْنِ النُّعْمَانِ عَنْ أَخِيهِ عَنْ دَاوُدَ بْنِ النُّعْمَانِ عَنْ أَبِي أَيُّوبَ الْخَزَّازِ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ إِنِّي جَرَّبْتُ جَوَارِيَ بَيْضَاءَ وَأَدْمَاءَ فَكَانَ بَيْنَهُنَّ بَوْنٌ.
5. Ahmad narrated from his father, from Ali ibn al-Nu’man, from his brother, from Dawud ibn al-Nu’man, from Abi Ayyub al-Khazzaz that Abu Abdillah al-Sadiq (as) said: "I have experienced [having] both light-skinned and dark-skinned maidservants, and there was a difference between them." (Allama al-Majlisi says: It means both of them have a preference)