Sunan Ibn Majah Book 23, Hadith 2749

حَدَّثَنَا مُحَمَّدُ بْنُ رُمْحٍ، أَنْبَأَنَا عَبْدُ اللَّهِ بْنُ لَهِيعَةَ، عَنْ عُقَيْلٍ، أَنَّهُ سَمِعَ نَافِعًا، يُخْبِرُ عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ مَا كَانَ مِنْ مِيرَاثٍ قُسِمَ فِي الْجَاهِلِيَّةِ فَهُوَ عَلَى قِسْمَةِ الْجَاهِلِيَّةِ وَمَا كَانَ مِنْ مِيرَاثٍ أَدْرَكَهُ الإِسْلاَمُ فَهُوَ عَلَى قِسْمَةِ الإِسْلاَمِ ‏"‏ ‏.‏

It was narrated from ‘Abdullah bin ‘Umar that the Messenger of Allah (ﷺ) said:“Whatever division of inheritance was made during the Ignorance period, stands according to the division of the Ignorance period, and whatever division of inheritance was made during Islam, it stands according to the division of Islam.”