Ahmad bin Hanbal أحمد بن حنبل · Shares of Inheritance (Kitab Al-Fara'id)

The Prophet (ﷺ) said: Knowledge has three categories; anything else is extra; a precise verse, or an established sunnah (practice), or a firm obligatory duty.

"To those also, to whom your right hand was pledged, give your portion." When the Emigrants came to Medina. they inherited from the Helpers without any blood-relationship with them for the brotherhood which the Messenger of Allah (ﷺ) established between them. When the following verse was revealed: "To (benefit) everyone we have appointed shares and heirs to property left by parent and relatives." it abrogated the verse: "To those also, to whom your right hand was pledged, give their due…