Sunan Abi Dawud, Book 18, Hadith 2891 (USC-MSA) ⓘ
Al-Hasan reported that Umar asked: Which of your knows what share the Messenger of Allah had given to the grandfather from the estate? Ma'qil ibn Yasar said: The Messenger of Allah gave him a sixth. He asked: Along with whom? He replied: I do not know. He said: You do not know; what is the use then?
حَدَّثَنَا وَهْبُ بْنُ بَقِيَّةَ، عَنْ خَالِدٍ، عَنْ يُونُسَ، عَنِ الْحَسَنِ، أَنَّ عُمَرَ، قَالَ أَيُّكُمْ يَعْلَمُ مَا وَرَّثَ رَسُولُ اللَّهِ صلى الله عليه وسلم الْجَدَّ فَقَالَ مَعْقِلُ بْنُ يَسَارٍ أَنَا وَرَّثَهُ رَسُولُ اللَّهِ صلى الله عليه وسلم السُّدُسَ . قَالَ مَعَ مَنْ قَالَ لاَ أَدْرِي . قَالَ لاَ دَرَيْتَ فَمَا تُغْنِي إِذًا .
also referenced under: Hadith 2897 (DarusSalam) & Hadith 2891 (Hasan)