While I was sitting with the Messenger of Allah ﷺ, a woman came to him and said, "I gave my mother a slave girl as charity, and she has now died."He replied, "Your reward is confirmed, and the inheritance has returned the Jariya to you."She asked, "Messenger of Allah, she owed a month of fasting. Shall I fast on her behalf?"He said, "Fast on her behalf."She asked, "She never performed the pilgrimage. Shall I perform it on her behalf?"He said, "Perform the pilgrimage on her behalf."In another narration, the fast owed was two months.
بينا أنا جالس عند رسول الله ﷺ إذ أتته امرأة. فقالت: إني تصدقت على أمي بجارية، وإنها ماتت. قال: فقال: وجب أجرك. وردها عليك الميراث قالت: يا رسول الله، إنه كان عليها صوم شهر أفأصوم عنها؟ قال: صومي عنها قالت: إنها لم تحج قط، أفأحج عنها؟ قال: حجي عنها. وفي رواية: صوم شهرين.
Muslim narrated it in the Book of Fasting (1149) through Abdullah bin Ata, from Abdullah bin Abdullah [i.e., Sulayman] bin Burayda, with this wording. In another version, through Abdullah bin Ata al-Makki, from Sulayman bin Burayda, from his father, similarly. And he said, "Fasting a month."I say, the apparent meaning of the hadith indicates that the deceased's guardian fasts on his behalf, whether the fast is from Ramadan or from a vow, because the obligation remains attached to the deceased, and because the Prophet ﷺ compared it to a debt, and a debt is discharged on behalf of the deceased to clear his obligation. This is the view of the people of hadith, as Ibn Hajar said in Fath al-Bari (4/193).Tirmidhi said, "The scholars have differed on this matter. Some of them said that fasting is performed on behalf of the deceased. This is the view of Ahmad and Ishaq, who said, if the deceased owed a vowed fast, it should be fasted on his behalf, and if he owed a make-up fast from Ramadan, food should be given on his behalf. Malik, Sufyan, and Shafii said that no one fasts on behalf of another." End of quote.I say, as for Shafii, he made the ruling in his earlier position contingent on the soundness of the hadith, as Bayhaqi related in Al-Marifah (6/309). And he said in Al-Khilafiyyat, "This matter is established, and I know of no disagreement among the people of hadith regarding its soundness, so it must be acted upon." It is also related from Shafii that he said, "Whatever I have said, if something sound from the Prophet ﷺ contradicts it, then follow the hadith and do not follow my opinion."Abu Hanifa and Malik held that no one fasts on behalf of the deceased, by analogy with prayer. The preferred view is what Ahmad said, that a vowed fast is fasted on the deceased's behalf, because it has no substitute, unlike the fast of Ramadan, which has a substitute, namely feeding the poor. This is also the view of Ibn Abbas, as mentioned by Abu Dawud (2401). If the guardians fast on behalf of the deceased, there is no harm in that, given the general wording of the hadith, and they may fast however they wish, together or separately, whether thirty men each fast a single day, or one man fasts thirty days, or three men divide it so that each fasts ten days. All of these are valid.As for what is related from Ibn Umar, from the Prophet ﷺ, that he said, "Whoever dies owing a month's fast, let food be given on his behalf in place of each day, to a poor person," this is daif. It was narrated by Tirmidhi (718), Ibn Majah (1757), and Ibn Khuzayma (2056), all through Ashath, from Muhammad bin Abu Layla, from Nafi, from Ibn Umar.Muhammad in this chain is attributed in three different ways. He appears without a specified lineage in Tirmidhi's version, who said, "In my view, he is Ibn Abdul-Rahman bin Abu Layla." In Ibn Majah's version, he is attributed to Ibn Sirin, as Mizzi and others have noted. And in Ibn Khuzayma's version, he is attributed to Abdul-Rahman bin Abu Layla, and this is sahih.The chain is daif because of Muhammad bin Abdul-Rahman bin Abu Layla, who has poor memory. It also contains, as the narrator from him, Ashath bin Sawwar, who is likewise daif. Ibn Khuzayma said, "There is something troubling in my mind regarding Ashath bin Sawwar, may Allah have mercy on him, due to his poor memory." And Tirmidhi said, "We do not know the hadith of Ibn Umar as a raised report except through this route, and the sahih version from Ibn Umar is that it is his own statement, not attributed to the Prophet."