Language:
كتاب الحيض
6  
Menstrual Periods
(6)
Chapter: A menstruating women should leave observing Saum (fasting)
(6)
باب تَرْكِ الْحَائِضِ الصَّوْمَ
Sahih al-Bukhari 304

Narrated Abu Sa`id Al-Khudri:

Once Allah's Messenger (ﷺ) went out to the Musalla (to offer the prayer) of `Id-al-Adha or Al-Fitr prayer. Then he passed by the women and said, "O women! Give alms, as I have seen that the majority of the dwellers of Hell-fire were you (women)." They asked, "Why is it so, O Allah's Messenger (ﷺ) ?" He replied, "You curse frequently and are ungrateful to your husbands. I have not seen anyone more deficient in intelligence and religion than you. A cautious sensible man could be led astray by some of you." The women asked, "O Allah's Messenger (ﷺ)! What is deficient in our intelligence and religion?" He said, "Is not the evidence of two women equal to the witness of one man?" They replied in the affirmative. He said, "This is the deficiency in her intelligence. Isn't it true that a woman can neither pray nor fast during her menses?" The women replied in the affirmative. He said, "This is the deficiency in her religion."

حَدَّثَنَا سَعِيدُ بْنُ أَبِي مَرْيَمَ، قَالَ أَخْبَرَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، قَالَ أَخْبَرَنِي زَيْدٌ ـ هُوَ ابْنُ أَسْلَمَ ـ عَنْ عِيَاضِ بْنِ عَبْدِ اللَّهِ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، قَالَ خَرَجَ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي أَضْحًى ـ أَوْ فِطْرٍ ـ إِلَى الْمُصَلَّى، فَمَرَّ عَلَى النِّسَاءِ فَقَالَ ‏"‏ يَا مَعْشَرَ النِّسَاءِ تَصَدَّقْنَ، فَإِنِّي أُرِيتُكُنَّ أَكْثَرَ أَهْلِ النَّارِ ‏"‏‏.‏ فَقُلْنَ وَبِمَ يَا رَسُولَ اللَّهِ قَالَ ‏"‏ تُكْثِرْنَ اللَّعْنَ، وَتَكْفُرْنَ الْعَشِيرَ، مَا رَأَيْتُ مِنْ نَاقِصَاتِ عَقْلٍ وَدِينٍ أَذْهَبَ لِلُبِّ الرَّجُلِ الْحَازِمِ مِنْ إِحْدَاكُنَّ ‏"‏‏.‏ قُلْنَ وَمَا نُقْصَانُ دِينِنَا وَعَقْلِنَا يَا رَسُولَ اللَّهِ قَالَ ‏"‏ أَلَيْسَ شَهَادَةُ الْمَرْأَةِ مِثْلَ نِصْفِ شَهَادَةِ الرَّجُلِ ‏"‏‏.‏ قُلْنَ بَلَى‏.‏ قَالَ ‏"‏ فَذَلِكَ مِنْ نُقْصَانِ عَقْلِهَا، أَلَيْسَ إِذَا حَاضَتْ لَمْ تُصَلِّ وَلَمْ تَصُمْ ‏"‏‏.‏ قُلْنَ بَلَى‏.‏ قَالَ ‏"‏ فَذَلِكَ مِنْ نُقْصَانِ دِينِهَا ‏"‏‏.‏
Reference : Sahih al-Bukhari 304
In-book reference : Book 6, Hadith 9
USC-MSA web (English) reference : Vol. 1, Book 6, Hadith 301
  (deprecated numbering scheme)