Muwatta Malik, Book 18, Hadith 688 (In-Book) ⓘ

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."

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