"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»