'Ubaidullah narrated on the authority of the same chain of transmitters that the Messenger of Allah ﷺ made a mention of Ramadan and said: The month may consist of twenty-nine days, and it may be thus, thus and thus, and (he further) said: Calculate it, but he did not say thirty.

وَحَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ، حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ عُبَيْدِ اللَّهِ، بِهَذَا الإِسْنَادِ وَقَالَ ذَكَرَ رَسُولُ اللَّهِ ﷺ رَمَضَانَ فَقَالَ " الشَّهْرُ تِسْعٌ وَعِشْرُونَ الشَّهْرُ هَكَذَا وَهَكَذَا وَهَكَذَا " . وَقَالَ " فَاقْدِرُوا لَهُ " . وَلَمْ يَقُلْ " ثَلاَثِينَ " .