What is the ruling on inheritance between non-believers if their religions differ?
Chapter on Distant Kindred (Dhawu al-Arham)
Al-Mughni
Book of Inheritance Shares (Farā'id)
Primary text
There are differing opinions transmitted from Ahmad concerning whether different forms of disbelief constitute one religion or multiple distinct religions for the purpose of inheritance. One reported view, favored by Al-Khallal, Hammad, Ibn Shubrumah, Abu Hanifah, Al-Shafi'i, and Dawud, is that all forms of disbelief constitute a single religion, allowing mutual inheritance. This is argued based on the general mentions of inheritance between parents and children in the Book of Allah, which should remain general unless specifically exempted by Shari'ah. Additionally, the Quranic verse {And those who disbelieve are allies to one another} (Quran 8:73) is general concerning all disbelievers.
Supporting text
A second view, favored by Abu Bakr and many scholars, is that disbelief comprises distinct religions, preventing mutual inheritance. This relies on the specific narration, "The people of two different religions do not inherit from each other," which qualifies the general statements in the Quran. A third position, articulated by Al-Qadi Abu Ya'la, states that disbelief is divided into three religions: Judaism, Christianity, and the religion of all others (those without a revealed Book). This view is attributed to Shu'ayb, 'Ata', 'Umar ibn 'Abd Al-'Aziz, and others. A fourth possibility inferred from Ahmad's statements suggests that disbelief encompasses numerous religions (e.g., Zoroastrianism as one, idol worship as another), meaning mutual inheritance does not occur between them. This latter view, attributed to 'Ali, Al-Zuhri, Rabi'ah, and supported by Ishaq, is held to be the soundest because it respects the principle that different religious groups lack mutual allegiance or unity in faith, analogous to the separation between Muslims and disbelievers.