[Machine] Abdullah bin Umar divorced his wife while she was menstruating. Umar then went to the Messenger of Allah ﷺ and informed him about this. The Messenger of Allah ﷺ told him to take her back, as she is his wife.
طَلَّقَ عَبْدُ اللهِ بْنُ عُمَرَ امْرَأَتَهُ وَهِيَ حَائِضٌ فَأَتَى عُمَرُ رَسُولَ اللهِ ﷺ فَأَخْبَرَهُ ذَلِكَ فَقَالَ رَسُولُ اللهِ ﷺ لِيُرَاجِعْهَا فَإِنَّهَا امْرَأَتُهُ
"I asked Ibn 'Umar about a man who divorced his wife when she was menstruating. He said: 'Do you know 'Abdullah bin 'Umar? He divorced his wife when she was menstruating then 'Umar came to the Prophet ﷺ (and told him what had happened). He ordered him to take her back.' I said: 'Will that be counted (as a divorce)?' He said: 'Do You think he was helpless and behaving foolishly? [i.e., Yes, it counts (as a divorce).]."'
تَعْرِفُ عَبْدَ اللَّهِ بْنَ عُمَرَ طَلَّقَ امْرَأَتَهُ وَهِيَ حَائِضٌ فَأَتَى عُمَرُ النَّبِيَّ ﷺ فَأَمَرَهُ أَنْ يُرَاجِعَهَا قُلْتُ أَيُعْتَدُّ بِتِلْكَ قَالَ أَرَأَيْتَ إِنْ عَجَزَ وَاسْتَحْمَقَ