The month may be twenty-nine days
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا مُحَمَّدُ بْنُ بِشْرٍ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ أَبِي خَالِدٍ، حَدَّثَنِي مُحَمَّدُ بْنُ سَعْدٍ، عَنْ سَعْدِ بْنِ أَبِي وَقَّاصٍ، - رضى الله عنه - قَالَ ضَرَبَ رَسُولُ اللَّهِ صلى الله عليه وسلم بِيَدِهِ عَلَى الأُخْرَى فَقَالَ " الشَّهْرُ هَكَذَا وَهَكَذَا " . ثُمَّ نَقَصَ فِي الثَّالِثَةِ إِصْبَعًا .
Sa'd b. Abi Waqqas (Allah be pleased with him) said that the Messenger of Allah (ﷺ) struck his hand against the other and (then with the gesture of his two hands) said: The month is thus, thus (two times). He then withdrew (one of) his fingers at the third turn.