‌Context & Objective: The will is a fundamental legal institution in Islamic law for regulating financial and non-financial affairs after death. While jurists traditionally view the will as a recommended act the principle that a closer relative excludes a more remote one often deprives grandchildren of an inheritance when their parent dies before the grandparent. This article investigates the concept of the Obligatory Bequest which is inspired by the Zahiri school and has been adopted by various Islamic countries. The primary research objective is to explore the legal and jurisprudential prospects of incorporating this institution into the Iranian legal order which currently does not recognize it. The research question focuses on whether religious texts and the rule of justice provide sufficient grounds for legislative reform to protect orphaned descendants.
 ‌Method & Approach: This study employs a doctrinal research method to analyze religious and legal texts. The approach involves a critical re-examination of Quranic verses and prophetic traditions related to bequests. The researcher examines the divergent views of Muslim scholars including the Imami school and the Zahiri perspectives of Ibn Hazm (D. 1064). Furthermore, the study evaluates the existing legal structures in Islamic nations and Iranian civil law to determine the feasibility of adopting mandatory wills. This analytical framework assesses the linguistic interpretations of mandatory language in Sharia sources to establish a basis for legal change.
 ‌Findings: The research identifies two main jurisprudential theories regarding the obligation to make a will. The majority view denies the legal obligation and interprets the Quranic phrase "a right upon the God-fearing" (Surah al-Baqarah, V. 180: Ḥaqqan ʿalā al-Muttaqīn) as a moral recommendation for the pious. However, another significant theory supports the obligation by citing the mandatory expression "it is prescribed for you" (Kutiba ʿalaykum) in Surah al-Baqarah which is identical to the language used to mandate fasting. The findings suggest that an obligatory bequest can effectively allocate a portion of the estate to grandchildren to represent the share of their deceased parent. Additionally, the rule of justice and equity supports this institution because it prevents the unfair impoverishment of grandchildren whose parents may have contributed to the family wealth.
 ‌Conclusion: The Obligatory Bequest serves as an essential tool for achieving justice and equity within the Islamic inheritance system. While not yet recognized in Iran the study concludes that there are solid religious foundations and valid jurisprudential interpretations to support its legislation. Implementing this reform would fill a significant gap in the legal system and prevent social resentment caused by the exclusion of vulnerable heirs. The article finally recommends that the Iranian legislature should adopt this institution to harmonize traditional inheritance rules with modern social needs and religious principles of mercy.