Al-Kāfi
Hadith 4672ـ أَحْمَدُ بْنُ مُحَمَّدٍ عَنْ عُثْمَانَ بْنِ عِيسَى عَنْ سَمَاعَةَ قَالَ سَأَلْتُهُ عَمَّنْ يَقْضِي شَهْرَ رَمَضَانَ مُنْقَطِعاً قَالَ إِذَا حَفِظَ أَيَّامَهُ فَلا بَأْسَ.
2. Ahmad ibn Muhammad has narrated from ‘Uthman ibn ‘Isa from Sama‘ah, who has said the following: “I once asked abu ‘ Abd Allah (a.s.), about a man who fasts Qada’ (compensatory fast) for the fast of the month of Ramadan in separate times. He (the Imam) said, It is not harmful if he keeps the number of days without missing.’”