She said that the Prophet ﷺ came in to her one day and asked, "Do you have anything to eat?"We replied, "No."He said, "Then I am fasting."Then he came to us on another day, and we said, "Messenger of Allah, we have been given a gift of hays."He said, "Show it to me, for I had begun the day fasting." Then he ate.
دخل على النبي ﷺ ذات يوم فقال: هل عندكم شيء؟ فقلنا: لا، قال: فإني إذن صائم. ثم أتانا يوما آخر، فقلنا: يا رسول الله أهدي لنا حيس، فقال: أرينيه، فلقد أصبحت صائما، فأكل.
Muslim narrated it in the Book of Fasting (1154:17) from Abu Bakr bin Abu Shayba, who said, Waki narrated to us, from Talha bin Yahya, from his aunt Ayesha bint Talha, from Ayesha, mother of the believers, and he mentioned it.His words in the first hadith, "for I am fasting," end the hadith there. This means that he ﷺ had formed the intention to fast after morning had come, without having formed the intention the night before.As for his words, "then the Messenger of Allah ﷺ went out, and a gift was brought to us," this is a different hadith about a different day, for in it he broke his fast after having fasted. Waki made this explicit in the version at Abu Dawud (2455), which he narrated from Abu Bakr bin Abu Shayba, from Waki, with his chain. He said, and Waki added, "Then he came in on us another day, and we said, 'Messenger of Allah, some hays was given to us as a gift, so we kept it for you.' He said, 'Bring it closer.'" Talha said, "So he had begun the day fasting, and then broke his fast." End of quote.Likewise, in the wording of Muslim it also says, "then he came to us another day," which indicates that the incident occurred over two separate days, but the narrator merged the two days together in the first hadith.The hadith is evidence that one who is fasting a voluntary fast may break the fast without an excuse, and is not obligated to make it up. This is the view of Shafii, Ahmad, and Ishaq. Abu Hanifa and Malik forbade breaking such a fast and required making it up if one did break it. It appears that this hadith did not reach them.Something with the same meaning is what Nasai narrated (2323) by way of Sharik, from Talha bin Yahya bin Talha, from Mujahid, from Ayesha, who said, "The Messenger of Allah ﷺ came in on me on his rounds, and said, 'Do you have anything?' I said, 'I have nothing.' He said, 'Then I am fasting.'" She said, "Then he came in on me the second time, and some hays had been given to us as a gift, so I brought it to him, and he ate. I was surprised at this, so I said, 'Messenger of Allah, you came in on me while fasting, and now you have eaten hays?' He said, 'Yes, Ayesha. The standing of one who fasts outside Ramadan, or outside making up a missed day of Ramadan, or as a voluntary fast, is like the standing of a man who sets aside a portion of his wealth as charity, then generously gives away from it whatever he wishes and carries it through, while withholding from it whatever remains and keeps it back.'"In its chain is Sharik, that is, Ibn Abdullah Nakhai, the judge, who is truthful but errs frequently, and whose memory deteriorated after he took up the judgeship in Kufa.