According to search-discovered classical Islamic scholarship, the disallowance of nepotism is a core principle of social justice derived from key Quranic events and verses. The foundational ruling is established in Quran 33:40, which, as explained by Tafsir authorities like Ibn Kathir and Al-Qurtubi, was revealed to abolish the pre-Islamic customs surrounding adoption, specifically in the case of the Prophet's adopted son, Zayd ibn Harithah. [1, 2] By declaring that "Muhammad is not the father of any of your men," the verse legally and socially separated biological lineage from spiritual and communal ties, thereby dismantling a system where inherited or adopted status could confer undue privilege. This specific ruling serves as a powerful precedent for the broader Islamic prohibition of favoritism (Al-Mahsubiyyah). It is thematically supported by verses commanding absolute justice, even against relatives (4:135), the rendering of trusts to the most deserving (4:58), and the declaration that piety (Taqwa) is the only true measure of honor (49:13). The synthesis of these verses establishes a clear Islamic framework for meritocracy, where competence, integrity, and piety are the legitimate criteria for responsibility, not kinship or personal favoritism.