Hadith 806:21
'Amr ibn al-Haytham Abu Qatan narrated to us, Yunus—meaning ibn Abi Ishaq—narrated to us, from his father, from 'Amr ibn Maymun, who said: 'Umar witnessed [a gathering] and he had gathered the companions of the Messenger of Allah, peace and blessings of Allah be upon him, during his lifetime and his health. He adjured them by Allah: "Who among you heard the Messenger of Allah, peace and blessings of Allah be upon him, mention anything regarding the grandfather?" Ma'qil ibn Yasar stood up and said: "I heard the Messenger of Allah, peace and blessings of Allah be upon him, [say]: 'A mandatory share was brought to him in which there was a grandfather, and he gave him a third or a sixth.'" He ['Umar] said: "And what was the mandatory share?" He said: "I do not know." He said: "What prevented you from knowing?"
حدثنا عمرو بن الهيثم أبو قطن، حدثنا يونس يعني ابن أبي إسحاق، عن أبيه، عن عمرو بن ميمون، شهد عمر قال: وقد كان جمع أصحاب رسول الله صلى الله عليه وسلم في حياته وصحته، فناشدهم الله من، سمع رسول الله صلى الله عليه وسلم ذكر في الجد شيئا، فقام معقل بن يسار، فقال: سمعت رسول الله صلى الله عليه وسلم، " أتي بفريضة فيها جد، فأعطاه ثلثا أو سدسا "، قال: وما الفريضة؟ قال: لا أدري، قال: ما منعك أن تدري؟