Sunan Abi Dawud, Hadith 3304

Narrated Ibn 'Abbas: A woman came to the Prophet and said (to him) that one month's fast was due from her mother who had died. May I fulfill them on her behalf? He asked: Suppose some debt was due from your mother, would you pay it ? She replied: Yes. He said: So the debt due to Allah is the one which most deserves to be paid.

حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا يَحْيَى، قَالَ سَمِعْتُ الأَعْمَشَ، ح وَحَدَّثَنَا مُحَمَّدُ بْنُ الْعَلاَءِ، حَدَّثَنَا أَبُو مُعَاوِيَةَ، عَنِ الأَعْمَشِ، - الْمَعْنَى - عَنْ مُسْلِمٍ الْبَطِينِ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ، ‏:‏ أَنَّ امْرَأَةً، جَاءَتْ إِلَى النَّبِيِّ صلى الله عليه وسلم فَقَالَتْ ‏:‏ إِنَّهُ كَانَ عَلَى أُمِّهَا صَوْمُ شَهْرٍ أَفَأَقْضِيهِ عَنْهَا فَقَالَ ‏:‏ ‏"‏ لَوْ كَانَ عَلَى أُمِّكِ دَيْنٌ أَكُنْتِ قَاضِيَتَهُ ‏"‏ ‏.‏ قَالَتْ ‏:‏ نَعَمْ ‏.‏ قَالَ ‏:‏ ‏"‏ فَدَيْنُ اللَّهِ أَحَقُّ أَنْ يُقْضَى ‏"‏ ‏.‏

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also referenced under: Hadith 3310 (DarusSalam)