Man Lā Yaḥḍuruh al-Faqīh
Hadith 10954308 - وَ سَأَلَ مُحَمَّدُ بْنُ مَنْصُورٍ مُوسَى بْنَ جَعْفَرٍ عَلَيْهِمَا اَلسَّلاَمُ : عَنْ رَجُلٍ نَذَرَ صِيَاماً فَثَقُلَ اَلصَّوْمُ عَلَيْهِ قَالَ "تَصَدَّقُ عَنْ كُلِّ يَوْمٍ بِمُدٍّ مِنْ حِنْطَةٍ".
Hadith.4308 - Muhammad ibn Mansur asked Imam Musa ibn Jafar Al-Kadhim (as) about a man who made a vow to fast but found fasting to be too difficult for him.
Imam (as) said: "He should give charity for each day in the amount of one mudd of wheat."