Muwatta Malik, Book 29, Hadith 3 (USC-MSA)

Yahya related to me from Malik from Yahya ibn Said from Abu Bakr ibn Hazm thatUmar ibn Abd al-Aziz had asked him what people said about the 'irrevocable' divorce, and Abu Bakr had replied that Aban ibn Uthman had clarified that it was declared only once. Umar ibn Abd al- Aziz said, "Even if divorce had to be declared a thousand times, the'irrevocable' would use them all up. A person who says, 'irrevocably' has cast the furthest limit."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ أَبِي بَكْرِ بْنِ حَزْمٍ، أَنَّ عُمَرَ بْنَ عَبْدِ الْعَزِيزِ، قَالَ لَهُ الْبَتَّةُ مَا يَقُولُ النَّاسُ فِيهَا قَالَ أَبُو بَكْرٍ فَقُلْتُ لَهُ كَانَ أَبَانُ بْنُ عُثْمَانَ يَجْعَلُهَا وَاحِدَةً ‏.‏ فَقَالَ عُمَرُ بْنُ عَبْدِ الْعَزِيزِ لَوْ كَانَ الطَّلاَقُ أَلْفًا مَا أَبْقَتِ الْبَتَّةُ مِنْهَا شَيْئًا مَنْ قَالَ الْبَتَّةَ فَقَدْ رَمَى الْغَايَةَ الْقُصْوَى ‏.‏

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also referenced under: Book 29, Hadith 1155 (In-Book)