Fasting Continuously and All the Time
Al-Kāfi|Volume 4|Book 2|Chapter 16
5ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ عُثْمَانَ بْنِ عِيسَى عَنْ سَمَاعَةَ قَالَ سَأَلْتُهُ عَنْ صَوْمِ الدَّهْرِ فَكَرِهَهُ وَقَالَ لا بَأْسَ أَنْ يَصُومَ يَوْماً وَيُفْطِرَ يَوْماً.
5. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ‘Uthman ibn ‘Isa from Sama‘ah, who has said the following: “I once asked him (the Imam) عليه السلام, about fasting forever. He (the Imam) disliked it and said, ‘It is not harmful to fast one day and not to fast the next day.’”
- Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (6/262)
- Ṣaḥīḥ al-Kāfī, vol. 2, p. 69