مِنْهُ مَا يَتَعَلَّقُ بِزَمَانٍ بِعَيْنِهِ،
Translation: Some obligatory fasts are attached to a specific period.
“A specified time” means that the fast’s day is already assigned. Ramadan is fixed by its month; a valid vow specifying an exact day likewise has a fixed date.
The fixed-date rule does not give someone unrestricted choice to shift an ordinary Ramadan obligation to another date. A missed Ramadan day is separately classified as qada.
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Kitab al-Sawm: Categories of Fasting and Rules of Intention
مِنْهُ مَا يَتَعَلَّقُ بِزَمَانٍ بِعَيْنِهِ،
Translation: Some obligatory fasts are attached to a specific period.
“A specified time” means that the fast’s day is already assigned. Ramadan is fixed by its month; a valid vow specifying an exact day likewise has a fixed date.
The fixed-date rule does not give someone unrestricted choice to shift an ordinary Ramadan obligation to another date. A missed Ramadan day is separately classified as qada.