The Book of Fasting
22/70. Chapter:
The fast of the Prophet
Sunan an-Nasai
أَخْبَرَنَا مُحَمَّدُ بْنُ النَّضْرِ بْنِ مُسَاوِرٍ الْمَرْوَزِيُّ، قَالَ حَدَّثَنَا حَمَّادٌ، عَنْ مَرْوَانَ أَبِي لُبَابَةَ، عَنْ عَائِشَةَ، قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَصُومُ حَتَّى نَقُولَ مَا يُرِيدُ أَنْ يُفْطِرَ وَيُفْطِرُ حَتَّى نَقُولَ مَا يُرِيدُ أَنْ يَصُومَ .
It was narrated that 'Aishah said: "The Messenger of Allah used to fast until we said: 'He does not want to break his fast.' And he used not to fast until we said: 'He does not want to fast."'
Reference : Sunan an-Nasa'i 2347In-book reference : Book 22, Hadith 258English translation : Vol. 3, Book 22, Hadith 2349