"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).'"
أَنَّهُ قَالَ آلَى رَسُولُ اللَّهِ ﷺ مِنْ نِسَائِهِ شَهْرًا فَأَقَامَ فِي مَشْرُبَةٍ تِسْعًا وَعِشْرِينَ يَوْمًا قَالُوا يَا رَسُولَ اللَّهِ إِنَّكَ آلَيْتَ شَهْرًا فَقَالَ الشَّهْرُ تِسْعٌ وَعِشْرُونَ