Jami` at-Tirmidhi, Hadith 733 ⓘ
Aishah, the Mother of the Believers, narrated: "The Messenger of Allah visited me one day and said: 'Do you have anything (to eat)?'" She said: "I said: 'No.' He said: 'Then I am fasting.'"
حَدَّثَنَا هَنَّادٌ، حَدَّثَنَا وَكِيعٌ، عَنْ طَلْحَةَ بْنِ يَحْيَى، عَنْ عَمَّتِهِ، عَائِشَةَ بِنْتِ طَلْحَةَ عَنْ عَائِشَةَ أُمِّ الْمُؤْمِنِينَ، قَالَتْ دَخَلَ عَلَىَّ رَسُولُ اللَّهِ صلى الله عليه وسلم يَوْمًا فَقَالَ " هَلْ عِنْدَكُمْ شَيْءٌ " . قَالَتْ قُلْتُ لاَ . قَالَ " فَإِنِّي صَائِمٌ " .
also referenced under: Book 8, Hadith 52 (In-Book) & Volume 2, Book 6, Hadith 733 (DarusSalam)