Sahih Muslim 1473
Sahih Muslim · Book 18: The Book of Divorce · Expiation must be offered by one who declares his wife to be unlawful for him but does not intend divorce thereby
Ibn Abbas (Allah be pleased with them) reported:
حَدَّثَنَا يَحْيَى بْنُ بِشْرٍ الْحَرِيرِيُّ ، حَدَّثَنَا مُعَاوِيَةُ، - يَعْنِي ابْنَ سَلاَّمٍ - عَنْ يَحْيَى، بْنِ أَبِي كَثِيرٍ أَنَّ يَعْلَى بْنَ حَكِيمٍ ، أَخْبَرَهُ أَنَّ سَعِيدَ بْنَ جُبَيْرٍ أَخْبَرَهُ أَنَّهُ، سَمِعَ ابْنَ عَبَّاسٍ ، قَالَ إِذَا حَرَّمَ الرَّجُلُ عَلَيْهِ امْرَأَتَهُ فَهْىَ يَمِينٌ يُكَفِّرُهَا وَقَالَ { لَقَدْ كَانَ لَكُمْ فِي رَسُولِ اللَّهِ أُسْوَةٌ حَسَنَةٌ}
When a man declares his wife unlawful for himself that is an oath which must be atoned, and he said: There is in the Messenger of Allah (ﷺ) a noble pattern for you.