Sunan an-Nasai Book 27, Hadith 3557

أَخْبَرَنَا عَلِيُّ بْنُ حُجْرٍ، قَالَ أَنْبَأَنَا إِسْمَاعِيلُ، عَنْ أَيُّوبَ، عَنْ نَافِعٍ، قَالَ كَانَ ابْنُ عُمَرَ إِذَا سُئِلَ عَنِ الرَّجُلِ، طَلَّقَ امْرَأَتَهُ وَهِيَ حَائِضٌ فَيَقُولُ أَمَّا إِنْ طَلَّقَهَا وَاحِدَةً أَوِ اثْنَتَيْنِ فَإِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم أَمَرَهُ أَنْ يُرَاجِعَهَا ثُمَّ يُمْسِكَهَا حَتَّى تَحِيضَ حَيْضَةً أُخْرَى ثُمَّ تَطْهُرَ ثُمَّ يُطَلِّقَهَا قَبْلَ أَنْ يَمَسَّهَا وَأَمَّا إِنْ طَلَّقَهَا ثَلاَثًا فَقَدْ عَصَيْتَ اللَّهَ فِيمَا أَمَرَكَ بِهِ مِنْ طَلاَقِ امْرَأَتِكَ وَبَانَتْ مِنْكَ امْرَأَتُكَ ‏.‏

When Ibn 'Umar was asked about a man who divorced his wife when she was menstruating, he would say:"If it is the first or second divorce, the Messenger of Allah would tell him to take her back and keep her until she has menstruated again and purified herself, then divorce her before having intercourse with her. But if it was three simultaneous divorces, then you have disobeyed Allah with regard to the way in which divorce should be conducted and your wife has become irrevocably divorced