Yahya related to me from Malik from Yahya ibn Said that he had heard that Muawiya ibn Abi Sufyan wrote to Zayd ibn Thabit asking him about the grandfather. Zayd ibn Thabit wrote to him, "You have written to me asking me about the grandfather. Allah knows best. That is part of what is only determined by the amirs, i.e. the khalifs. I was present with two khalifs before you who gave the grandfather a half with one sibling, and a third with two. If there were more siblings, they did not decrease his third."  

عَنِ الْجَدِّ وَاللَّهُ أَعْلَمُ وَذَلِكَ مِمَّا لَمْ يَكُنْ يَقْضِي فِيهِ إِلاَّ الأُمَرَاءُ يَعْنِي الْخُلَفَاءَ وَقَدْ حَضَرْتُ الْخَلِيفَتَيْنِ قَبْلَكَ يُعْطِيَانِهِ النِّصْفَ مَعَ الأَخِ الْوَاحِدِ وَالثُّلُثَ مَعَ الاِثْنَيْنِ فَإِنْ كَثُرَتِ الإِخْوَةُ لَمْ يُنَقِّصُوهُ مِنَ الثُّلُثِ  

[Machine] "And Allah knows best, and that is what was not decreed except by the rulers, meaning the caliphs. I have witnessed two caliphates before you, they allot him half with one brother and a third with two. If there are many siblings, the third is not diminished from him. He said, and I, Malik, have heard that Sulayman ibn Yasar said, Umar ibn al-Khattab, Uthman ibn Affan, and Zaid ibn Thabit obliged the third to the paternal grandfather with the siblings."  

وَاللهُ أَعْلَمُ وَذَلِكَ مَا لَمْ يَكُنْ يَقْضِي فِيهِ إِلَّا الْأُمَرَاءُ يَعْنِي الْخُلَفَاءَ وَقَدْ حَضَرْتُ الْخَلِيفَتَيْنِ قَبْلَكَ يُعْطِيَانِهِ النِّصْفَ مَعَ الْأَخِ الْوَاحِدِ وَالثُّلُثَ مَعَ الِاثْنَيْنِ فَإِنْ كَثُرَ الْإِخْوَةُ لَمْ يُنْقِصَاهُ مِنَ الثُّلُثِ 12434 قَالَ وَأنا مَالِكٌ أَنَّهُ بَلَغَهُ عَنْ سُلَيْمَانَ بْنِ يَسَارٍ أَنَّهُ قَالَ فَرَضَ عُمَرُ بْنُ الْخَطَّابِ وَعُثْمَانُ بْنُ عَفَّانَ وَزَيْدُ بْنُ ثَابِتٍ ؓ لِلْجَدِّ الثُّلُثَ مَعَ الْإِخْوَةِ