It is narrated from Abu Salamah that Abdur Rahman bin Awf (may Allah be pleased with him) bought a slave woman from Asim bin Adi (may Allah be pleased with him), and he was informed that she had a husband, so he returned her.
Hadith Referenceمسند الإمام الشافعي / كتاب البيوع / 1380
Hadith Takhrijاسناده ضعیف لانقطاعه، فان أبا سلمة بن عبدالرحمن لم يسمع من ابيه شيئًا: اخرجه البيهقي: 5/ 323 - وفى المعرفة السنن والآثار له (3619)۔