That ʿAbdullah bin ʿUmar told him that he had divorced his wife while she was in her menses so ʿUmar informed Messenger of Allah ﷺ of that. Messenger of Allah ﷺ became very angry at that and said, "(Ibn ʿUmar must return her to his house and keep her as his wife till she becomes clean and then menstruates and becomes clean again, whereupon, if he wishes to divorce her, he may do so while she is still clean and before having any sexual relations with her, for that is the legally prescribed period for divorce as Allah has ordered."  

أَخْبَرَهُ أَنَّهُ طَلَّقَ امْرَأَتَهُ وَهْىَ حَائِضٌ فَذَكَرَ عُمَرُ لِرَسُولِ اللَّهِ ﷺ فَتَغَيَّظَ فِيهِ رَسُولُ اللَّهِ ﷺ ثُمَّ قَالَ لِيُرَاجِعْهَا ثُمَّ يُمْسِكْهَا حَتَّى تَطْهُرَ ثُمَّ تَحِيضَ فَتَطْهُرَ فَإِنْ بَدَا لَهُ أَنْ يُطَلِّقَهَا فَلْيُطَلِّقْهَا طَاهِرًا قَبْلَ أَنْ يَمَسَّهَا فَتِلْكَ الْعِدَّةُ كَمَا أَمَرَهُ اللَّهُ  

[Machine] He divorced his wife while she was menstruating, and he mentioned that to Umar. Umar then went to the Messenger of Allah ﷺ and informed him. So the Messenger of Allah ﷺ said: "Let him keep her until she menstruates again, other than this menstruation, then she should purify herself. If it appears to him that he should divorce her, then he should divorce her as Allah commanded. And if it appears to him that he should keep her, then he should keep her."  

أَنَّهُ طَلَّقَ امْرَأَتَهُ وَهِيَ حَائِضٌ فَذَكَرَ ذَلِكَ إِلَى عُمَرَ فَانْطَلَقَ عُمَرُ إِلَى رَسُولِ اللهِ ﷺ فَأَخْبَرَهُ فَقَالَ رَسُولُ اللهِ ﷺ لِيُمْسِكْهَا حَتَّى تَحِيضَ غَيْرَ هَذِهِ الْحَيْضَةِ ثُمَّ تَطْهُرَ فَإِنْ بَدَا لَهُ أَنْ يُطَلِّقَهَا فَلْيُطَلِّقْهَا كَمَا أَمَرَهُ اللهُ ﷻ وَإِنْ بَدَا لَهُ أَنْ يُمْسِكَهَا فَلْيُمْسِكْهَا  

‘Abd Allah (bin Umar) said that he divorced his wife while she was menstruating. ‘Umar mentioned the matter to the Messenger of Allah ﷺ. The Messenger of Allah ﷺ became angry and said “Command him, he must take her back and keep her back till she is purified, then has another menstrual period and is purified. Then if he desires he may divorce her during the period of purity before he has intercourse with her. This is the divorce for waiting period as commanded by Allaah, the Exalted. (Using translation from Abū Dāʾūd 2182)   

أَخْبَرَهُ أَنَّهُ طَلَّقَ امْرَأَتَهُ وَهِيَ حَائِضٌ فَذَكَرَ ذَلِكَ عُمَرُ لِرَسُولِ اللهِ ﷺ فَتَغَيَّظَ فِيهِ رَسُولُ اللهِ ﷺ ثُمَّ قَالَ رَسُولُ اللهِ ﷺ لِيُرَاجِعْهَا ثُمَّ لِيُمْسِكْهَا حَتَّى تَطْهُرَ ثُمَّ تَحِيضَ ثُمَّ تَطْهُرَ فَإِنْ بَدَا لَهُ أَنْ يُطَلِّقَهَا فَلْيُطَلِّقْهَا طَاهِرًا قَبْلَ أَنْ يَمَسَّهَا فَتِلْكَ الْعِدَّةُ كَمَا أَمَرَ اللهُ ﷻ