"I asked Ibn Umar about a man who divorced his wife while she was menstruating. So he said: 'Don't you know Abdullah bin Umar?' Indeed he divorced his wife while she was menstruating, so Umar asked the Prophet about that, and he ordered him to take her back.'" He said: "I said: And that divorce is counted? He said: And that divorce is counted? He said: 'What else would you think if he was helpless and foolish?'"
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا حَمَّادُ بْنُ زَيْدٍ، عَنْ أَيُّوبَ، عَنْ مُحَمَّدِ بْنِ سِيرِينَ، عَنْ يُونُسَ بْنِ جُبَيْرٍ، قَالَ سَأَلْتُ ابْنَ عُمَرَ عَنْ رَجُلٍ، طَلَّقَ امْرَأَتَهُ وَهِيَ حَائِضٌ فَقَالَ هَلْ تَعْرِفُ عَبْدَ اللَّهِ بْنَ عُمَرَ فَإِنَّهُ طَلَّقَ امْرَأَتَهُ وَهِيَ حَائِضٌ فَسَأَلَ عُمَرُ النَّبِيَّ صلى الله عليه وسلم فَأَمَرَهُ أَنْ يُرَاجِعَهَا . قَالَ قُلْتُ فَيُعْتَدُّ بِتِلْكَ التَّطْلِيقَةِ قَالَ فَمَهْ أَرَأَيْتَ إِنْ عَجَزَ وَاسْتَحْمَقَ
Tirmizi
The Book on Divorce and Li'an • Hadith 1177