The Sufficient (Vol 4) · Hadith 566 (#Ḥadīth #9)

9ـ مُحَمَّدُ بْنُ إِسْمَاعِيلَ عَنِ الْفَضْلِ بْنِ شَاذَانَ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ إِبْرَاهِيمَ بْنِ عَبْدِ الْحَمِيدِ عَنْ أَبِي الْحَسَنِ الرِّضَا صَلَوَاتُ الله عَلَيْهِ قَالَ سَأَلْتُهُ عَنِ الرَّجُلِ يَجْعَلُ لله عَزَّ وَجَلَّ عَلَيْهِ صَوْمَ يَوْمٍ مُسَمًّى قَالَ يَصُومُهُ أَبَداً فِي السَّفَرِ وَالْحَضَرِ.

9. Muhammad ibn ‘Isma‘il has narrated from al-Fadl ibn Shadhan from Ibn Abi ‘Umayr from Ibrahim ibn ‘Abd al-Hamid who has said the following: “I once asked abu al-Hassan, al-Rida’ , about a man who places upon himself for Allah, most Majestic, most Glorious, fasting of a definite day. He (the Imam) said, ‘He is required to fast definitely, regardless of being on a journey or at home.’”

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