Muwatta Imam Malik Book of Divorce, Hadith 48

Yahya related to me from Malik from Ibn Shihab from Said ibn al- Musayyab that Nufay, a mukatab of Umm Salama, the wife of the Prophet ﷺ divorced his free wife twice, so he asked Uthman ibn Affan for an opinion, and he said, "She is haram for you."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّ نُفَيْعًا، مُكَاتَبًا كَانَ لأُمِّ سَلَمَةَ زَوْجِ النَّبِيِّ ﷺ طَلَّقَ امْرَأَةً حُرَّةً تَطْلِيقَتَيْنِ فَاسْتَفْتَى عُثْمَانَ بْنَ عَفَّانَ فَقَالَ حَرُمَتْ عَلَيْكَ .