Muwatta Malik, Book 29, Hadith 4 (USC-MSA)

Yahya related to me from Malik from Ibn Shihab that Marwan ibn al-Hakam decided that if someone made three pronouncements of divorce, he had divorced his wife irrevocably. Malik said, "That is what I like best of what I have heard on the subject." 29.2 Divorce by Euphemistic Statements

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، أَنَّ مَرْوَانَ بْنَ الْحَكَمِ، كَانَ يَقْضِي فِي الَّذِي يُطَلِّقُ امْرَأَتَهُ الْبَتَّةَ أَنَّهَا ثَلاَثُ تَطْلِيقَاتٍ ‏.‏ قَالَ مَالِكٌ وَهَذَا أَحَبُّ مَا سَمِعْتُ إِلَىَّ فِي ذَلِكَ ‏.‏

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also referenced under: Book 29, Hadith 1156 (In-Book)