Sunan Ibn Majah, Book 7, Hadith 1727 (In-Book) ⓘ
It was narrated that Abu Hurairah said: "(The months in which) We fasted twenty-nine days at the time of the Messenger of Allah, were more than (the months in which) we fasted thirty days.
حَدَّثَنَا مُجَاهِدُ بْنُ مُوسَى، حَدَّثَنَا الْقَاسِمُ بْنُ مَالِكٍ الْمُزَنِيُّ، حَدَّثَنَا الْجُرَيْرِيُّ، عَنْ أَبِي نَضْرَةَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ مَا صُمْنَا عَلَى عَهْدِ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ تِسْعًا وَعِشْرِينَ أَكْثَرُ مِمَّا صُمْنَا ثَلاَثِينَ .
also referenced under: Hadith 1658 (Reference) & Volume 2, Book 7, Hadith 1658 (DarusSalam)