"I divorced my wife when she was menstruating. 'Umar mentioned that to the Messenger of Allah and he said: 'Tell him to take her back until she becomes pure (i.e., her period ends), then she has her period (again), then she becomes pure (again), then if he wishes he may divorce her before having sexual relations with her, and if he wishes he may keep her. This is the waiting period that Allah has enjoined.'" (Using translation from Ibn Mājah 2019)   

أَنَّهُ طَلَّقَ امْرَأَتَهُ وَهِيَ حَائِضٌ فَذَكَرَ ذَلِكَ عُمَرُ لِلنَّبِيِّ ﷺ فَقَالَ «مُرْهُ أَنْ يُرَاجِعَهَا وَيُمْسِكَهَا حَتَّى تَطْهُرَ ثُمَّ تَحِيضَ ثُمَّ تَطْهُرَ ثُمَّ إِنْ شَاءَ أَمْسَكَ وَإِنْ شَاءَ طَلَّقَ قَبْلَ أَنْ يَمَسَّ فَتِلْكَ الْعِدَّةُ الَّتِي أَمَرَ اللَّهُ أَنْ يُطَلَّقَ لَهَا النِّسَاءُ»  

[Machine] "When the Prophet ﷺ divorced the wife of Ibn Umar, he said, 'Let him take her back and then divorce her while she is in a state of purity.' Abu Muhammad said, 'This was narrated by Ibn Al-Mubarak, Wakie, or Hamil.'"  

لِلنَّبِيِّ ﷺ حِينَ طَلَّقَ ابْنُ عُمَرَ امْرَأَتَهُ فَقَالَ «مُرْهُ فَلْيُرَاجِعْهَا ثُمَّ لِيُطَلِّقْهَا وَهِيَ طَاهِرَةٌ» قَالَ أَبُو مُحَمَّد «رَوَاهُ ابْنُ الْمُبَارَكِ وَوَكِيعٌ أَوْ حَامِلٌ»