Muwatta Imam Malik Book of Fasting, Hadith 50

Yahya related to me from Malik from Ibn Shihab that A'isha and Hafsa, the wives of the Prophet ﷺ began fasting voluntarily one morning and then food was given to them and they broke their fast with it. Then the Messenger of Allah ﷺ came in. A'isha said, "Hafsa asked, anticipating me in speech - she took after her father Umar - 'Messenger of Allah, A'isha and I began the morning fasting voluntarily and then food was given us and we broke the fast with it.' The Messenger of Allah ﷺ said, 'Fast another day in its place.' "

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، أَنَّ عَائِشَةَ، وَحَفْصَةَ، زَوْجَىِ النَّبِيِّ ﷺ أَصْبَحَتَا صَائِمَتَيْنِ مُتَطَوِّعَتَيْنِ فَأُهْدِيَ لَهُمَا طَعَامٌ فَأَفْطَرَتَا عَلَيْهِ فَدَخَلَ عَلَيْهِمَا رَسُولُ اللَّهِ ﷺ قَالَتْ عَائِشَةُ فَقَالَتْ حَفْصَةُ وَبَدَرَتْنِي بِالْكَلاَمِ - وَكَانَتْ بِنْتَ أَبِيهَا - يَا رَسُولَ اللَّهِ إِنِّي أَصْبَحْتُ أَنَا وَعَائِشَةُ صَائِمَتَيْنِ مُتَطَوِّعَتَيْنِ فَأُهْدِيَ إِلَيْنَا طَعَامٌ فَأَفْطَرْنَا عَلَيْهِ . فَقَالَ رَسُولُ اللَّهِ ﷺ " اقْضِيَا مَكَانَهُ يَوْمًا آخَرَ " .