Sahih Muslim Book - 18, Hadith - 3666

حَدَّثَنَا يَحْيَى بْنُ يَحْيَى أَخْبَرَنَا خَالِدُ بْنُ عَبْدِ اللَّهِ عَنْ عَبْدِ الْمَلِكِ عَنْ أَنَسِ بْنِ سِيرِينَ قَالَ سَأَلْتُ ابْنَ عُمَرَ عَنِ امْرَأَتِهِ الَّتِى طَلَّقَ فَقَالَ طَلَّقْتُهَا وَهْىَ حَائِضٌ فَذُكِرَ ذَلِكَ لِعُمَرَ فَذَكَرَهُ لِلنَّبِىِّ -صلى الله عليه وسلم- فَقَالَ « مُرْهُ فَلْيُرَاجِعْهَا فَإِذَا طَهَرَتْ فَلْيُطَلِّقْهَا لِطُهْرِهَا ». قَالَ فَرَاجَعْتُهَا ثُمَّ طَلَّقْتُهَا لِطُهْرِهَا. قُلْتُ فَاعْتَدَدْتَ بِتِلْكَ التَّطْلِيقَةِ الَّتِى طَلَّقْتَ وَهْىَ حَائِضٌ قَالَ مَا لِىَ لاَ أَعْتَدُّ بِهَا وَإِنْ كُنْتُ عَجَزْتُ وَاسْتَحْمَقْتُ.

It was narrated that Anas bin Sirin said: "I asked Ibn 'Umar about his wife whom he divorced. He said: 'I divorced her while she was menstruating, and I told 'Umar about that, and he told the Prophet (s.a.w), who said: "Tell him to take her back, then when she becomes pure, he may divorce her when she is pure." He said: 'So I took her back, then I divorced her when she was pure.' I said: 'Was that divorce that you gave her while she was menstruating counted as such? He said: 'Why wouldn't I count it? It must be counted even if I failed and acted foolishly."'