"The Messenger of Allah swore not to come to his wives for a month, and twenty-nine days passed. I said: 'Did you not wives to keep away from you wives for a month? I have counted twenty-nine days.' The Messenger of Allah said: 'The month is twenty-nine days."' (Using translation from Nasāʾī 2131)  

أَقْسَمَ رَسُولُ اللهِ ﷺ لَا يَدْخُلُ عَلَى نِسَائِهِ شَهْرًا فَلَبِثَ تِسْعًا وَعِشْرِينَ فَقُلْتُ أَلَيْسَ قَدْ كُنْتَ آلَيْتَ شَهْرًا فَعَدَدْتُ الْأَيَّامَ تِسْعًا وَعِشْرِينَ قَالَ رَسُولُ اللهِ ﷺ «الشَّهْرُ تِسْعٌ وَعِشْرُونَ»  

"I was very keen to ask 'Umar bin Al-Khattab about the two wives of the Messenger of Allah to whom Allah said: If you two turn in repentance to Allah, (it will be better for you), your hearts are indeed so inclined." And he quoted the Hadith. He said concerning it:' "The from his wives for twenty-nine days because of that, when Hafsah had made her disclosure to Aishah. He had said: 'I will not enter upon them for a month,' because he was so upset with them when Allah, the Mighty and Sublime, informed him of what they had said. When twenty-nine days had passed, he entered upon 'Aishah, so he started with her. Aishah, said to him: 'O Messenger of Allah, you swore not to enter upon us for a month, and now twenty-nine days have passed; we have been counting them.' The Messenger of Allah said; 'The month is twenty-nine days."' (Using translation from Nasāʾī 2132)  

عَنِ الْمَرْأَتَيْنِ مِنْ أَزْوَاجِ النَّبِيِّ ﷺ اللَّتَيْنِ قَالَ اللهُ لَهُمَا {إِنْ تَتُوبَا إِلَى اللهِ فَقَدْ صَغَتْ قُلُوبُكُمَا} [التحريم 4] وَسَاقَ الْحَدِيثَ وَقَالَ فِيهِ فَاعْتَزَلَ رَسُولُ اللهِ ﷺ نِسَاءَهُ مِنْ أَجْلِ ذَلِكَ الْحَدِيثِ حِينَ أَفْشَتْهُ حَفْصَةُ إِلَى عَائِشَةَ تِسْعًا وَعِشْرِينَ لَيْلَةً قَالَتْ عَائِشَةُ وَكَانَ قَالَ «مَا أَنَا بِدَاخِلٍ عَلَيْهِنَّ شَهْرًا» مِنْ شِدَّةِ مَوْجِدَتِهِ عَلَيْهِنَّ حِينَ حَدَّثَهُ اللهُ حَدِيثَهُنَّ فَلَمَّا مَضَتْ تِسْعٌ وَعِشْرُونَ لَيْلَةً دَخَلَ عَلَى عَائِشَةَ فَبَدَأَ بِهَا فَقَالَتْ لَهُ عَائِشَةُ إِنَّكَ قَدْ كُنْتَ آلَيْتَ يَا رَسُولَ اللهِ أَلَّا تَدْخُلَ عَلَيْهِنَّ شَهْرًا وَإِنَّا أَصْبَحْنَا مِنْ تِسْعٍ وَعِشْرِينَ لَيْلَةً نَعُدُّهَا عَدَدًا فَقَالَ رَسُولُ اللهِ ﷺ «الشَّهْرُ تِسْعٌ وَعِشْرُونَ لَيْلَةً»