Qabisah bin Dhu'ayb said: A grandmother came to Sayyiduna Abu Bakr al-Siddiq (may Allah be pleased with him) and asked him about her inheritance in the Book of Allah. Sayyiduna Abu Bakr (may Allah be pleased with him) said to her: There is nothing for you in the Book of Allah, and I know of nothing for you in the Sunnah of the Messenger of Allah (peace and blessings be upon him), so go back until I ask the people. So he asked the people, and al-Mughirah bin Shu'bah (may Allah be pleased with him) said: "I was present with the Messenger of Allah (peace and blessings be upon him); he (peace and blessings be upon him) gave her one sixth." Sayyiduna Abu Bakr (may Allah be pleased with him) said: Is there anyone else with you? Sayyiduna Muhammad bin Maslamah al-Ansari (may Allah be pleased with him) stood up and said the same as al-Mughirah (may Allah be pleased with him) had said, so Sayyiduna Abu Bakr (may Allah be pleased with him) implemented this decision for her. Then the other grandmother came to Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) asking for her inheritance, and he said: There is nothing for you in the Book of Allah, and the decision that was made was only for someone other than you, and I will not add anything to the fixed shares (fara'id); but it is that same one sixth: if the two of you share in it, it will be divided between you, and whichever of you is left alone will receive all of it.
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 16560