Sunan an-Nasa'i, Book 22, Hadith 237 (In-Book) ⓘ

It was narrated from 'Aishah, the mother of the Believers, that the Prophet used to come to her when he was fasting and say: "Do you have anything this morning that you can give me to eat?" we would say no, and he would say: "I am fasting." Then after that he came and she said: "I have been given a gift." He said: "What is it?" she said: "Hais." He said: "I started the day fasting," but then he ate.

أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا يَحْيَى، قَالَ حَدَّثَنَا طَلْحَةُ بْنُ يَحْيَى، قَالَ حَدَّثَتْنِي عَائِشَةُ بِنْتُ طَلْحَةَ، عَنْ عَائِشَةَ أُمِّ الْمُؤْمِنِينَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يَأْتِيهَا وَهُوَ صَائِمٌ فَقَالَ ‏"‏ أَصْبَحَ عِنْدَكُمْ شَىْءٌ تُطْعِمِينِيهِ ‏"‏ ‏.‏ فَنَقُولُ لاَ ‏.‏ فَيَقُولُ ‏"‏ إِنِّي صَائِمٌ ‏"‏ ‏.‏ ثُمَّ جَاءَهَا بَعْدَ ذَلِكَ فَقَالَتْ أُهْدِيَتْ لَنَا هَدِيَّةٌ ‏.‏ فَقَالَ ‏"‏ مَا هِيَ ‏"‏ ‏.‏ قَالَتْ حَيْسٌ ‏.‏ قَالَ ‏"‏ قَدْ أَصْبَحْتُ صَائِمًا ‏"‏ ‏.‏ فَأَكَلَ ‏.‏