حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ حَدَّثَنَا شُعْبَةُ عَنِ الْأَسْوَدِ بْنِ قَيْسٍ سَمِعْتُ سَعِيدَ بْنَ عَمْرِو بْنِ سَعِيدٍ يُحَدِّثُ أَنَّهُ سَمِعَ ابْنَ عُمَرَ يُحَدِّثُ عَنْ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّهُ قَالَ إِنَّا أُمَّةٌ أُمِّيَّةٌ لَا نَكْتُبُ وَلَا نَحْسُبُ الشَّهْرُ هَكَذَا وَهَكَذَا وَهَكَذَا وَعَقَدَ الْإِبْهَامَ فِي الثَّالِثَةِ وَالشَّهْرُ هَكَذَا وَهَكَذَا وَهَكَذَا يَعْنِي تَمَامَ ثَلَاثِينَ
مسند امام احمد بن حنبل · Hadith 5017
Sa'eed ibn 'Urwah ibn Sa'eed narrated that he heard Ibn 'Umar narrate that the Prophet (peace and blessings of Allah be upon him} said: "We are an unlettered nation, we do not write or calculate. The month may be like this and this and this.” - and the third time he tucked his thumbaway -“ or the month may be like this and this and this" meaning thirty.
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020