عَنْ عَمْرِو بْنِ خَارِجَةَ الْخُشَنِيِّ رَضِيَ اللَّهُ عَنْهُ أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ خَطَبَهُمْ عَلَى رَاحِلَتِهِ وَإِنَّ رَاحِلَتَهُ لَتَقْصَعُ بِجِرَّتِهَا وَأَنَّ لُعَابَهَا يَسِيلُ بَيْنَ كَتِفَيَّ فَقَالَ إِنَّ اللَّهَ عَزَّ وَجَلَّ قَدْ قَسَمَ لِكُلِّ إِنْسَانٍ نَصِيبَهُ مِنَ الْمِيرَاثِ فَلَا تَجُوزُ وَصِيَّةٌ لِوَارِثٍ الْحَدِيثَ
Narrated by Sayyiduna Amr bin Kharijah Khushani رضي الله عنه: The Noble Prophet صلى الله عليه وآله وسلم delivered a sermon to us while he صلى الله عليه وآله وسلم was mounted on his riding animal, and his animal was chewing the cud and its saliva was flowing onto my shoulders. He صلى الله عليه وآله وسلم said: Allah Almighty has fixed the share of every person in inheritance, therefore it is not permissible to make a bequest in favor of an heir.