"The Messenger of Allah vowed to stay away from his wives for a month, so he stayed in a loft for twenty-nine days. They said: 'O Messenger of Allah, your vow was for a month,' so he said: 'The month is twenty-nine (days).'" (Using translation from Tirmidhī 690)   

أَنَّهُ قَالَ آلَى رَسُولُ اللَّهِ ﷺ مِنْ نِسَائِهِ وَكَانَتِ انْفَكَّتْ رِجْلُهُ فَأَقَامَ فِي مَشْرُبَةٍ تِسْعًا وَعِشْرِينَ ثُمَّ نَزَلَ قَالُوا يَا رَسُولَ اللَّهِ آلَيْتَ شَهْرًا قَالَ «الشَّهْرُ تِسْعٌ وَعِشْرُونَ»  

"The Messenger of Allah swore to keep away from his wives and declared them as unlawful for him, so he made something permissible forbidden, and he offered expiation for having sworn to do so." (Using translation from Ibn Mājah 2072)  

«آلَى رَسُولُ اللَّهِ ﷺ مِنْ نِسَائِهِ فَجَعَلَ الْحَرَامَ حَلَالًا وَجَعَلَ فِي الْيَمِينِ كَفَّارَةً»