Muwatta Malik 685
Fasting
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ أَبِي سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ، أَنَّهُ سَمِعَ عَائِشَةَ، زَوْجَ النَّبِيِّ صلى الله عليه وسلم تَقُولُ إِنْ كَانَ لَيَكُونُ عَلَىَّ الصِّيَامُ مِنْ رَمَضَانَ فَمَا أَسْتَطِيعُ أَصُومُهُ حَتَّى يَأْتِيَ شَعْبَانُ
Yahya related to me from Malik from Yahya ibn Said from Abu Salama ibn Abd ar-Rahman that he heard A'isha, the wife of the Prophet, may Allah bless him and grant him peace, say, "I used to have to make up days from Ramadan and not be able to do them until Shaban came
Grading: Salim al-Hilali: Mauquf Sahih
Text from the public-domain hadith-api dataset. Numbering follows that dataset and can differ by a few from some printed editions — check the wording, not only the number.