Abu Musa was asked regarding (the inheritance of) a daughter, a son's daughter, and a sister. He said, "The daughter will take one-half and the sister will take one-half. If you go to Ibn Mas`ud, he will tell you the same." Ibn Mas`ud was asked and was told of Abu Musa's verdict. Ibn Mas`ud then said, "If I give the same verdict, I would stray and would not be of the rightly-guided. The verdict I will give in this case, will be the same as the Prophet (ﷺ) did, i.e. one-half is for daughter, and one-sixth for the son's daughter, i.e. both shares make two-thirds of the total property; and the rest is for the sister." Afterwards we cams to Abu Musa and informed him of Ibn Mas`ud's verdict, whereupon he said, "So, do not ask me for verdicts, as long as this learned man is among you."
Commentary on the Laws of Inheritance (Al-Faraa'id)
This narration from Sahih al-Bukhari 6736 demonstrates the critical importance of precise knowledge in Islamic inheritance law and the humility of the Companions in deferring to superior understanding.
The Initial Disagreement
Abu Musa al-Ash'ari initially ruled that the daughter receives half and the sister receives half, following apparent textual evidence that daughters get half when alone and sisters get half when no descendants exist.
Ibn Mas'ud corrected this by applying the Prophet's precise ruling: the daughter takes 1/2, the son's daughter takes 1/6 (together making 2/3 as ordained for female descendants), and the sister receives the remainder.
Scholarly Analysis
This case involves "al-ʿawl" (proportional reduction) where the sister receives the residual after fixed shares. The son's daughter as a residuary heir ("ʿaṣabah") through the son's representation receives her prescribed portion.
Ibn Mas'ud's knowledge of the Prophet's specific ruling on this complex case demonstrates the necessity of transmitted knowledge (naql) alongside rational deduction (ra'y) in fiqh.
Legal Principles Derived
When multiple female descendants exist, they collectively receive two-thirds, distributed according to their proximity to the deceased.
A sister inherits as a residuary heir when no male siblings exist and after fixed shares are distributed.
Scholarly humility requires acknowledging superior knowledge and deferring to those with more authentic transmission of Prophetic precedents.
Significance for Islamic Jurisprudence
This narration establishes that inheritance rulings require specific knowledge of Prophetic traditions and cannot be deduced through analogy alone. Abu Musa's gracious acceptance of correction exemplifies the proper conduct of scholars when clearer evidence emerges.