عَنْ عائِشَةَ رضي اللّه عَنْهَا عَنِ النبيّ صَلّى اللّهُ عَلَيْهِ وسَلَّم قَالَ: «مَنْ مَاتَ وَعَلَيْهِ صَوْمٌ، صَامَ عَنْهُ وَلِيُّهُ» متفقٌ عَلَيْهِ.
Aisha (may Allah be pleased with her) reported from the Prophet (peace and blessings be upon him) that he said: "Whoever dies while owing a fast, his guardian may fast on his behalf." Agreed upon.
الشرح · explanation
وَلِيُّهُ: الوَليّ: الْقَرِيبُ وَارِثًا كَانَ أوْ غَيْرَ وَارِثٍ.
"His guardian (waliyy)": the waliyy is the relative, whether an heir or not.
الدروس · lessons
أنّه يجوز للولي فقط أن يصوم عن قريبه إذا مات وفاته صوم واجب كان قد تمكن من قضائه، وإن شاء أخرج من تركته عن كل يوم مدًا من طعام، ولا يصوم الأجنبي إلا بإذنه. المُخْتَارُ جَوَازُ الصَّوْمِ عَمَّنْ مَاتَ وَعَلَيْهِ صَوْمٌ لِهَذَا الْحَدِيثِ.
That only the guardian may fast on behalf of his relative who dies having missed an obligatory fast that he was able to make up; and if he wishes, he may instead give, from the deceased's estate, a mudd of food for each day. A stranger may not fast on his behalf except with his permission. The preferred view is the permissibility of fasting on behalf of one who dies while owing a fast, on the basis of this hadith.