Sahih al-Bukhari 1959
Sahih al-Bukhari · Book 30: Fasting · If somebody breaks the Saum thinking that the sun has set
Narrated Abu Usama from Hisham bin 'Urwa from Fatima:
حَدَّثَنِي عَبْدُ اللَّهِ بْنُ أَبِي شَيْبَةَ ، حَدَّثَنَا أَبُو أُسَامَةَ ، عَنْ هِشَامِ بْنِ عُرْوَةَ ، عَنْ فَاطِمَةَ ، عَنْ أَسْمَاءَ بِنْتِ أَبِي بَكْرٍ ـ رضى الله عنهما ـ قَالَتْ أَفْطَرْنَا عَلَى عَهْدِ النَّبِيِّ صلى الله عليه وسلم يَوْمَ غَيْمٍ، ثُمَّ طَلَعَتِ الشَّمْسُ. قِيلَ لِهِشَامٍ فَأُمِرُوا بِالْقَضَاءِ قَالَ بُدٌّ مِنْ قَضَاءٍ. وَقَالَ مَعْمَرٌ سَمِعْتُ هِشَامًا لاَ أَدْرِي أَقْضَوْا أَمْ لاَ.
Asma bint Abi Bakr said, "We broke our fast during the lifetime of the Prophet (ﷺ) on a cloudy day and then the sun appeared." Hisham was asked, "Were they ordered to fast in lieu of that day?" He replied, "It had to be made up for." Ma`mar said, "I heard Hisham saying, "I don't know whether they fasted in lieu of that day or not."