Mishkat al-Masabih 3061
Inheritance and Wills
Shares of Inheritance - Section 2
Qabisa b. Dhu’aib said that when a grandmother came to Abu Bakr asking him for her share of an estate he told her that nothing was prescribed for her in God’s Book or in the sunna of God's Messenger, but asked her to go home till he had questioned the people. When he did so, al-Mughira b. Shu'ba said he had been present with God's Messenger when he gave her a sixth. Abu Bakr asked if anyone had been with him and Muhammad b. Maslama said the same as al- Mughira had said, so Abu Bakr made it apply to her. Another grand-mother came to ‘Umar asking him for her share of an estate and he said, “It is that sixth. If there are two of you it is shared between you, but whichever is the only one left gets it all.” Malik, Ahmad, Tirmidhi, Abu Dawud, Darimi and Ibn Majah transmitted it.