وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَلِيَّ بْنَ أَبِي طَالِبٍ، كَانَ يَقُولُ فِي الرَّجُلِ يَقُولُ لاِمْرَأَتِهِ أَنْتِ عَلَىَّ حَرَامٌ إِنَّهَا ثَلاَثُ تَطْلِيقَاتٍ ‏.‏ قَالَ مَالِكُ وَذَلِكَ أَحْسَنُ مَا سَمِعْتُ فِي ذَلِكَ ‏.‏

Yahya related to me from Malik that he had heard that Ali ibn AbiTalib used to say that if a man said to his wife, "You are haram forme," it counted as three pronouncements of divorce. Maliksaid, "That is the best of what I have heard on the subject." Translation Not Available

Book reference: Muwatta Imam Malik Book 29 Hadith 1158
Web reference: Muwatta Imam Malik Book 29 Hadith 6