وَعَنِ اِبْنِ عُمَرَ (رَضِيَ اَللَّهُ عَنْهُمَا
«أَنَّهُ طَلَّقَ اِمْرَأَتَهُ) وَهِيَ حَائِضٌ (فِي عَهْدِ رَسُولِ اَللَّهِ) صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ (فَسَأَلَ عُمَرُ رَسُولَ اَللَّهِ) صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَنْ ذَلِكَ ? فَقَالَ: «مُرْهُ فَلْيُرَاجِعْهَا، ثُمَّ لْيُمْسِكْهَا حَتَّى تَطْهُرَ، ثُمَّ تَحِيضَ، ثُمَّ تَطْهُرَ، ثُمَّ إِنْ شَاءَ أَمْسَكَ بَعْدُ، وَإِنْ شَاءَ طَلَّقَ بَعْدَ أَنْ يَمَسَّ، فَتِلْكَ اَلْعِدَّةُ اَلَّتِي أَمَرَ اَللَّهُ أَنْ تُطَلَّقَ لَهَا اَلنِّسَاءُ»
In the time of the Messenger of Allah (sallallahu alayhi wa sallam), he divorced his wife while she was menstruating, so Umar asked the Messenger of Allah (sallallahu alayhi wa sallam) about that and he replied, “Command him to take her back and keep her till she is purified (from menses), has another period, and is then purified.
If he then wishes he may keep her and if he wishes he may divorce her before having intercourse with her. That is the Iddah (period of waiting) which Allah commanded for the divorce of women.”.