Narrator:Ibn ‘Abbās
وَحَدَّثَنِي أَحْمَدُ بْنُ عُمَرَ الْوَكِيعِيُّ، حَدَّثَنَا حُسَيْنُ بْنُ عَلِيٍّ، عَنْ زَائِدَةَ، عَنْ سُلَيْمَانَ، عَنْ مُسْلِمٍ الْبَطِينِ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ، - رضى الله عنهما - قَالَ جَاءَ رَجُلٌ إِلَى النَّبِيِّ صلى الله عليه وسلم فَقَالَ يَا رَسُولَ اللَّهِ إِنَّ أُمِّي مَاتَتْ وَعَلَيْهَا صَوْمُ شَهْرٍ أَفَأَقْضِيهِ عَنْهَا فَقَالَ "
لَوْ كَانَ عَلَى أُمِّكَ دَيْنٌ أَكُنْتَ قَاضِيَهُ عَنْهَا " . قَالَ نَعَمْ . قَالَ " فَدَيْنُ اللَّهِ أَحَقُّ أَنْ يُقْضَى "
‘Abdullāh ibn ‘Abbās (may Allah be pleased with him) reported that a man came to the Prophet (may Allah's peace and blessings be upon him) and said: "O Messenger of Allah, my mother has died in a state that she had to observe the fast of a month. Should I complete it on her behalf?" Thereupon he said: "Would you not pay the debt if your mother had died without paying it?" He said: 'Yes.' He said: "The debt of Allah is more worthy of being repaid."
Another narration states that a woman came to the Prophet (may Allah's peace and blessings be upon him) and said: "O Messenger of Allah, my mother passed away and she took an oath to fast, should I fast on her behalf?" He said: "Tell me, if there was a debt due on your mother and you settled it, would it be enough?" She replied: 'Yes.' He said: "So, fast on behalf of your mother."
Reported by Muslim (No. 1148b), Al-Bukhari (No. 1852, 7315), Abu Dawud (No. 3310) and Ahmad (No. 1901, 2220).