Does a pilgrimage (Hajj) vowed through a vow suffice for the obligatory Hajj (Hajj al-Islam) if the person owes the obligatory Hajj?
General Chapter
Al-Mughni
Book of Hajj
Primary text
The primary recorded opinion attributed to Ahmad is that a vowed Hajj does not discharge the obligatory Hajj al-Islam. This view is supported by Ibn Umar, Anas, and Ata. The rationale is that one act of Hajj cannot fulfill two separate obligations, analogous to vowing two pilgrimages and performing only one. However, another view suggests that it does suffice because the person intended the pilgrimage for their vow, and it fulfills the obligation, similar to how an act of worship intended for both a supererogatory and obligatory purpose suffices for the obligatory one, according to one narration.
Supporting text
A reported opinion from Abu Talib, quoting Ahmad, states that if someone vowed to perform Hajj and owed the obligatory Hajj, and they initiate the Hajj with the intention of fulfilling the vow, it counts for the obligatory Hajj, and nothing else is due. This is likened to vowing to fast on the day someone arrives, and that day falls within Ramadan, where intending it for both the vow and the obligatory fast suffices, according to one narration. This latter view is held by Ibn Abbas and Ikrimah, citing an analogy involving praying four rak'ahs which fulfills both a vow to pray four and the obligatory Asr prayer.