It was narrated that 'Aishah the mother of the Believers, said: "The Messenger of Allah came one day and said: 'Do you have any food?' I said: 'No.' He came in to me on another occasion, and I said: 'O Messenger of Allah, we have been given some Hais.' He said: "Then I will break my fast today, although I had started my day fasting."'
It was narrated from Hafsah that the Prophet said: "Whoever does not have the intention of fasting from the night before, then there is no fast for him." (Daif)
Hamzah bin 'Abdullah bin 'Umar narrated that his father said: "Hafsah, the wife of the Prophet said: 'There is no fast for the one who does not intend (to fast) before dawn."'
Abdullah bin 'Amr bin Al-As said: "The Messenger of Allah said: 'The most beloved fasting to Allah, the mighty and sublime, is the fast of Dawud, peace be upon him. He used to fast one day and not the next. And the most beloved prayer to Allah, the mighty and sublime, is the prayer of Dawud, peace be upon him. He used to sleep half the night, stand for one-third of it (in prayer), and sleep for one-sixth of it."'
Hadiths 2345https://sunnah.com/nasai:2345
أَخْبَرَنَا الْقَاسِمُ بْنُ زَكَرِيَّا، قَالَ حَدَّثَنَا عُبَيْدُ اللَّهِ، قَالَ حَدَّثَنَا يَعْقُوبُ، عَنْ جَعْفَرٍ، عَنْ سَعِيدٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم لاَ يُفْطِرُ أَيَّامَ الْبِيضِ فِي حَضَرٍ وَلاَ سَفَرٍ .
It was narrated that Ibn 'Abbas said: "The Messenger of Allah would not break fast on the days of Al-Bid whether he was a resident or traveling."
It was narrated that Ibn 'Abbas said: "The Messenger of Allah would fast until we said he would not break his fast, and he would not fast until we said he does not want to fast. And he never fasted any month in full apart from Ramadan, from the time he came to Al-Madinah."
Hadiths 2347https://sunnah.com/nasai:2347
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."'
It was narrated that 'Aishah said: "I do not know that the Messenger of Allah recited the whole Quran in one night, or prayed Qiyam until morning, or ever fasted an entire month, except Ramadan."
Hadiths 2349https://sunnah.com/nasai:2349
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا حَمَّادٌ، عَنْ أَيُّوبَ، عَنْ عَبْدِ اللَّهِ بْنِ شَقِيقٍ، قَالَ سَأَلْتُ عَائِشَةَ عَنْ صِيَامِ النَّبِيِّ، صلى الله عليه وسلم قَالَتْ كَانَ يَصُومُ حَتَّى نَقُولَ قَدْ صَامَ وَيُفْطِرُ حَتَّى نَقُولَ قَدْ أَفْطَرَ وَمَا صَامَ رَسُولُ اللَّهِ صلى الله عليه وسلم شَهْرًا كَامِلاً مُنْذُ قَدِمَ الْمَدِينَةَ إِلاَّ رَمَضَانَ .
It was narrated that 'Abdullah bin Shaqiq said: "I asked 'Aishah about the fasting of the Messenger of Allah. She said: "The Messenger of Allah used to fast until we said: He is going to (continue to) fast, and he used not to fast until we said: He is not going to, and he did not fast for a whole month from the time he came to Al-Madinah, apart from Ramadan."'