Al-Muwatta Hadith 27.4

Yahya related to me from Malik from Ibn Shihab from Uthman ibn Ishaq ibn Kharasha that Qabisa ibn Dhu'ayb said, "A grandmother came to Abu Bakr as-Siddiq and asked him for her inheritance. Abu Bakr said to her, 'You have nothing in the Book of Allah, and I do not know that you have anything in the sunna of the Messenger of Allah, may Allah bless him and grant him peace. Go away therefore, until I have questioned the people.' (i.e.the Companions). He questioned the people, and al-Mughira ibn Shuba said, 'I was present with the Messenger of Allah, may Allah bless him and grant him peace, when he gave the grandmother a sixth.' Abu Bakr said, 'Was there anybody else with you?' Muhammad ibn Maslama al-Ansari stood up and said the like of what al-Mughira said. Abu Bakr as-Siddiq gave it to her. Then the other grandmother came to Umar ibn al-Khattab and asked him for her inheritance. He said to her, "You have nothing in the Book of Allah, and what has been decided is only for other than you, and I am not one to add to the fixed shares, other than that sixth. If there are two of you together, it is between you. If eitherof you is left alone with it, it is hers."