Hadith on Fasting: Making up missed fasts on behalf of deceased

Ibn Abbas reported: A woman came to the Messenger of Allah, peace and blessings be upon him, and she said, “My mother has died and she owed a month of fasting.” The Prophet said, “Do you think if she had a debt you would repay it on her behalf?” She said yes. The Prophet said, “The debts of Allah are more worthy to be repaid.

Source: Ṣaḥīḥ al-Bukhārī 1902, Ṣaḥīḥ Muslim 1132

Grade: Muttafaqun Alayhi (authenticity agreed upon) according to Al-Bukhari and Muslim

عَنْ ابْنِ عَبَّاسٍ رَضِيَ اللَّهُ عَنْهُمَا أَنَّ امْرَأَةً أَتَتْ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَتْ إِنَّ أُمِّي مَاتَتْ وَعَلَيْهَا صَوْمُ شَهْرٍ فَقَالَ أَرَأَيْتِ لَوْ كَانَ عَلَيْهَا دَيْنٌ أَكُنْتِ تَقْضِينَهُ قَالَتْ نَعَمْ قَالَ فَدَيْنُ اللَّهِ أَحَقُّ بِالْقَضَاءِ

1754 صحيح البخاري كتاب جزاء الصيد باب الحج والنذور عن الميت والرجل يحج عن المرأة

1148 صحيح مسلم كتاب الصيام باب قضاء الصيام عن الميت