حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ سَعِيدِ بْنِ عَمْرِو بْنِ سُلَيْمٍ الزُّرَقِيِّ، أَنَّهُ سَأَلَ الْقَاسِمَ بْنَ مُحَمَّدٍ عَنْ رَجُلٍ، طَلَّقَ امْرَأَةً إِنْ هُوَ تَزَوَّجَهَا فَقَالَ الْقَاسِمُ بْنُ مُحَمَّدٍ إِنَّ رَجُلاً جَعَلَ امْرَأَةً عَلَيْهِ كَظَهْرِ أُمِّهِ إِنْ هُوَ تَزَوَّجَهَا فَأَمَرَهُ عُمَرُ بْنُ الْخَطَّابِ إِنْ هُوَ تَزَوَّجَهَا أَنْ لاَ يَقْرَبَهَا حَتَّى يُكَفِّرَ كَفَّارَةَ الْمُتَظَاهِرِ ‏.‏

Yahya related to me from Malik from Said ibn Amr ibn Sulaym az-Zuraqi that he asked al-Qasim ibn Muhammad about a man who madedivorce conditional on his marrying a woman i.e. if he married her hewould automatically divorce her. Al-Qasim ibn Muhammad said, "If a manmarries a woman whom he has made as his mother's back, i.e. has madeharam for him, Umar ibn al-Khattab ordered him not to go near her ifhe married her until he had done the kaffara for pronouncing dhihar." Translation Not Available

Book Ref: Muwatta Imam Malik Book 29 Hadith 1176
Web Ref:  Muwatta Imam Malik Book 29 Hadith 20