Is a vow (nadhr) made by a slave to perform Hajj valid?
General Chapter
Al-Mughni
Book of Hajj
Primary text
The vow made by a slave to perform Hajj is valid because the slave is considered a legally accountable person, thus his vow is established just as it would be for a free person. However, the master has the right to prevent the slave from proceeding with the Hajj because doing so would result in the loss of the master's due right. This ruling is mentioned by Al-Qadi and Ibn Hamid.
Supporting text
A narration from Ahmad suggests that he disliked the master preventing the slave from fulfilling the vow. This indicates that prevention might be disliked (makruh) rather than forbidden (haram), given that fulfilling the vow involves performing an obligatory act. Alternatively, it might still be considered forbidden because the vow obligation, once established, is a duty, and the master cannot prevent him from fulfilling other obligations.