Sahih Muslim
Sahih Muslim 1080p
حَدَّثَنَا أَبُو كَامِلٍ الْجَحْدَرِيُّ، حَدَّثَنَا عَبْدُ الْوَاحِدِ بْنُ زِيَادٍ، حَدَّثَنَا الْحَسَنُ بْنُ عُبَيْدِ، اللَّهِ عَنْ سَعْدِ بْنِ عُبَيْدَةَ، قَالَ سَمِعَ ابْنُ عُمَرَ، - رضى الله عنهما - رَجُلاً يَقُولُ اللَّيْلَةَ لَيْلَةُ النِّصْفِ فَقَالَ لَهُ مَا يُدْرِيكَ أَنَّ اللَّيْلَةَ النِّصْفُ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " الشَّهْرُ هَكَذَا وَهَكَذَا " . وَأَشَارَ بِأَصَابِعِهِ الْعَشْرِ مَرَّتَيْنِ " وَهَكَذَا " . فِي الثَّالِثَةِ وَأَشَارَ بِأَصَابِعِهِ كُلِّهَا وَحَبَسَ أَوْ خَنَسَ إِبْهَامَهُ " .
Saad ibn Ubayda reported that Ibn Umar heard a man say, “Tonight is the middle of the month.” Ibn Umar asked him how he knew that tonight was the middle. He replied that he had heard the Messenger of Allah say that the month is like this and this, indicating ten with his fingers twice, and like this, indicating it a third time with all his fingers while holding back or folding his thumb.