Muwatta Malik, Book 31, Hadith 8 (USC-MSA)

Yahya related to me from Malik from Ibn Shihab from Abu Salama ibn Abd ar-Rahman ibn Awf that Abd ar-Rahman ibn Awf bought a slave- girl and found that she had a husband, so he returned her.

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ أَبِي سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ، أَنَّ عَبْدَ الرَّحْمَنِ بْنَ عَوْفٍ، ابْتَاعَ وَلِيدَةً فَوَجَدَهَا ذَاتَ زَوْجٍ فَرَدَّهَا ‏.‏

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also referenced under: Book 31, Hadith 1300 (In-Book)