حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، - رضى الله عنهما - عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ ذَكَرَ رَمَضَانَ فَقَالَ ‏"‏ لاَ تَصُومُوا حَتَّى تَرَوُا الْهِلاَلَ وَلاَ تُفْطِرُوا حَتَّى تَرَوْهُ فَإِنْ أُغْمِيَ عَلَيْكُمْ فَاقْدِرُوا لَهُ ‏"‏ ‏.‏

Ibn 'Umar (Allah be pleased with both of them) reported Allah's Messenger (ﷺ) as saying

The month (of Ramadan) may consist of twenty nine days, and Shu'ba (one of the narrators) (gave a practical demonstration how the Holy prophet (ﷺ) explained to them) by unfolding his hands thrice and folding his thumb at the third turn. 'Uqba (one of the narrators in this chain of transmitters) said: I think that he said that the month consists of thirty days and unfolded his palm three times.