Is performing a vowed act of worship (Nadr) before its specifically vowed time sufficient?

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If a person vows to fast a specific month or perform Hajj in a specific year and completes the act before that specified time, the act is not considered fulfilled. This is based on the principle that the vowed act is understood to be bound by its prescribed legal context. If one were to fast before Ramadan, it would not suffice; similarly, performing the vowed act early does not suffice because the condition of performing it at its stipulated time has been breached. This is analogous to an act not performed at all.