If anyone dies in a state (that he had to complete) some fasts, his heir must fast on his behalf.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ مَنْ مَاتَ وَعَلَيْهِ صِيَامٌ صَامَ عَنْهُ وَلِيُّهُ  

A woman came to the Messenger of Allah ﷺ and said: My mother has died, and fasts of a month are due from her. Thereupon he said: Don't you see that if debt was due from her, would you not pay it? She said: Yes (I would pay on her behalf). Thereupon he said: The debt of Allah deserves its payment more than (the payment of anyone else).  

أَنَّ امْرَأَةً أَتَتْ رَسُولَ اللَّهِ ﷺ فَقَالَتْ إِنَّ أُمِّي مَاتَتْ وَعَلَيْهَا صَوْمُ شَهْرٍ فَقَالَ أَرَأَيْتِ لَوْ كَانَ عَلَيْهَا دَيْنٌ أَكُنْتِ تَقْضِينَهُ قَالَتْ نَعَمْ قَالَ فَدَيْنُ اللَّهِ أَحَقُّ بِالْقَضَاءِ  

A man came to the Messenger of Allah ﷺ and said: Messenger of Allah, my mother has died (in a state) that she had to observe fasts of a month (of Ramadan). Should I complete (them) on her behalf? thereupon he (the Holy Prophet) said: Would you not pay the debt if your mother had died (without paying it)? He said: Yes. He (the Holy Prophet) said: The debt of Allah deserves more that it should he paid.  

جَاءَ رَجُلٌ إِلَى النَّبِيِّ ﷺ 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 قَالَ سُلَيْمَانُ فَقَالَ الْحَكَمُ وَسَلَمَةُ بْنُ كُهَيْلٍ جَمِيعًا وَنَحْنُ جُلُوسٌ حِينَ حَدَّثَ مُسْلِمٌ بِهَذَا الْحَدِيثِ فَقَالاَ سَمِعْنَا مُجَاهِدًا يَذْكُرُ هَذَا عَنِ ابْنِ عَبَّاسٍ  

This hadith has been narrated on the authority of Ibn 'Abbas (Allah be pleased with them) from the Messenger of Allah ﷺ.  

عَنِ النَّبِيِّ ﷺ بِهَذَا الْحَدِيثِ  

A woman came to the Messenger of Allah ﷺ and said: Messenger of Allah, my mother has died and there is due from her a fast of vow; should I fast on her behalf? Thereupon he said: You see that if your mother had died in debt, would it not have been paid on her behalf? She said: Yes. He (the Holy Prophet) said: Then observe fast on behalf of your mother.  

جَاءَتِ امْرَأَةٌ إِلَى رَسُولِ اللَّهِ ﷺ فَقَالَتْ يَا رَسُولَ اللَّهِ إِنَّ أُمِّي مَاتَتْ وَعَلَيْهَا صَوْمُ نَذْرٍ أَفَأَصُومُ عَنْهَا قَالَ أَرَأَيْتِ لَوْ كَانَ عَلَى أُمِّكِ دَيْنٌ فَقَضَيْتِيهِ أَكَانَ يُؤَدِّي ذَلِكِ عَنْهَا قَالَتْ نَعَمْ قَالَ فَصُومِي عَنْ أُمِّكِ  

When we were sitting with the Messenger of Allah ﷺ, a woman came to him and said: I had gifted to my mother a maid-servant, and now she (the mother) has died. Thereupon he (the Holy Prophet) said: There is a definite reward for you and she (the maid-servant) has been returned to you as an inheritance. She (that woman) again said: Fasts of a month (of Ramadan) are due upon her; should I observe them on her behalf? He (the Holy Prophet) said: Observe fasts on her behalf. She (again) said: She did not perform Hajj, should I perform it on her behalf? He (the Holy Prophet) said: Perform Hajj on her behalf.  

بَيْنَا أَنَا جَالِسٌ عِنْدَ رَسُولِ اللَّهِ ﷺ إِذْ أَتَتْهُ امْرَأَةٌ فَقَالَتْ إِنِّي تَصَدَّقْتُ عَلَى أُمِّي بِجَارِيَةٍ وَإِنَّهَا مَاتَتْ قَالَ فَقَالَ وَجَبَ أَجْرُكِ وَرَدَّهَا عَلَيْكِ الْمِيرَاثُ قَالَتْ يَا رَسُولَ اللَّهِ إِنَّهُ كَانَ عَلَيْهَا صَوْمُ شَهْرٍ أَفَأَصُومُ عَنْهَا قَالَ صُومِي عَنْهَا قَالَتْ إِنَّهَا لَمْ تَحُجَّ قَطُّ أَفَأَحُجُّ عَنْهَا قَالَ حُجِّي عَنْهَا  

I was sitting with the Messenger of Allah ﷺ ; the rest of the hadith is the same but with this variation that the (the narrator) said:" Fasts of two months."  

كُنْتُ جَالِسًا عِنْدَ النَّبِيِّ ﷺ بِمِثْلِ حَدِيثِ ابْنِ مُسْهِرٍ غَيْرَ أَنَّهُ قَالَ صَوْمُ شَهْرَيْنِ  

A woman came to the Messenger of Allah ﷺ, and the rest of the hadith is the same, but he said:" Fasting of one month."  

جَاءَتِ امْرَأَةٌ إِلَى النَّبِيِّ ﷺ فَذَكَرَ بِمِثْلِهِ وَقَالَ صَوْمُ شَهْرٍ  

" Fasting of two months."  

وَقَالَ صَوْمُ شَهْرَيْنِ  

" Fasting for one month."  

أَتَتِ امْرَأَةٌ إِلَى النَّبِيِّ ﷺ بِمِثْلِ حَدِيثِهِمْ وَقَالَ صَوْمُ شَهْرٍ