The month is thus and thus and thus (i. e. pointing with his fingers thrice), and he held back his thumb at the third time (in order to show that it can also consist of twenty-nine days).  

سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ الشَّهْرُ هَكَذَا وَهَكَذَا وَهَكَذَا وَقَبَضَ إِبْهَامَهُ فِي الثَّالِثَةِ  

The month is thus and thus and thus (i. e. pointing with his fingers thrice), and he held back his thumb at the third time (in order to show that it can also consist of twenty-nine days). (Using translation from Muslim 1080i)  

سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ الشَّهْرُ هَكَذَا وَهَكَذَا وَهَكَذَا وَقَبَضَ إِبْهَامَهُ فِي الثَّالِثَةِ  

The Prophet ﷺ said, "The month is like this and this," (at the same time he showed the fingers of both his hands thrice) and left out one thumb on the third time. (Using translation from Bukhārī 1908)  

قَالَ رَسُولُ اللَّهِ ﷺ «إِنَّ الشَّهْرَ هَكَذَا وَهَكَذَا» وَخَنَسَ الْإِبْهَامَ فِي الثَّالِثَةِ