The Sufficient (Vol 4) · Hadith 559 (#Ḥadīth #2)

2ـ عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ عَلِيِّ بْنِ أَحْمَدَ بْنِ أَشْيَمَ قَالَ كَتَبَ الْحُسَيْنُ إِلَى الرِّضَا (عَلَيْهِ السَّلاَم) جُعِلْتُ فِدَاكَ رَجُلٌ نَذَرَ أَنْ يَصُومَ أَيَّاماً مَعْلُومَةً فَصَامَ بَعْضَهَا ثُمَّ اعْتَلَّ فَأَفْطَرَ أَ يَبْتَدِئُ فِي صَوْمِهِ أَمْ يَحْتَسِبُ بِمَا مَضَى فَكَتَبَ إِلَيْهِ يَحْتَسِبُ مَا مَضَى.

2. A number of our people have narrated from Ahmad ibn Muhammad from Ali ibn Ahmad ibn ‘Ushaym who has said the following: “Al-Husayn once wrote to al-Rida’ , saying, ‘I pray to Allah to keep my soul in service for your cause, a man had vowed to fast for certain days and fasted a few days, then he became ill and stopped fasting. Is he required to start fasting all over again or are the days that he had fasted are counted?’ He (the Imam) wrote the answer that said, ‘The days that he had fasted are also counted.’”

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).