What is the ruling if a person makes I'tikaf a vow (Nadr)?

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If a person vows to perform I'tikaf, fulfilling that vow becomes obligatory upon them. Scholars, including Ibn al-Mundhir, agree upon this obligation based on the general principle concerning vows. This is established by the Prophet's saying: "Whoever vows to obey Allah, then let him obey Him," transmitted by Al-Bukhari. Furthermore, when 'Umar vowed to observe I'tikaf for a night in the Sacred Mosque, the Prophet, peace be upon him, commanded him: "Fulfill your vow," narrated by Al-Bukhari and Muslim.