A valid vow specifying “next Thursday” fixes the date. A separate vow promising “one fast” without a date is an unspecified vow.
Quduri places the first with fixed-day obligations and the second with outstanding liabilities. The intention deadlines differ, assuming each vow has otherwise been validly made.
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Kitab al-Sawm: Categories of Fasting and Rules of Intention
A valid vow specifying “next Thursday” fixes the date. A separate vow promising “one fast” without a date is an unspecified vow.
Quduri places the first with fixed-day obligations and the second with outstanding liabilities. The intention deadlines differ, assuming each vow has otherwise been validly made.