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 (PBUH) 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. Translation Not Available

Book Ref: Sahih Muslim Book 13 Hadith 2389
Web Ref:  Sahih Muslim Book 6 Hadith 1086 a