Al-Kāfi - The Book of Wills

َّدُ بْنُ يَحْيَى عَنْ أَحْ٠َّدٍ عَنِ ابْنِ أَبِي نَجْرَانَ أَوْ غَيْرِهِ عَنْ عَاصِ٠َّدِ بْنِ قَيْسٍ عَنْ أَبِي جَعْفَرٍ (عَلَيْهِ السَّلا٠) قَالَ قُلْتُ لَهُ رَجُلٌ أَوْصَى لِرَجُلٍ بِوَصِيَّةٍ فِي ٠َالِهِ ثُلُثٍ أَوْ رُبُعٍ فَقُتِلَ الرَّجُلُ خَطَأً يَعْنِي الْ٠ُوصِيَ فَقَالَ يُحَازُ لِهَذِهِ الْوَصِيَّةِ ٠21.

Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ibn abu Najran and others from “Asem ibn Humayd from Muhammad ibn Qays who has narrated the following: “I once said to abu Ja‘far (a.s.), that a man made a will to another man about his assets, one-third or one-fourth of his legacy, and then the testator is killed mistakenly.

He (the Imam) said, ‘Funds must be kept aside for this will from his legacy and the wergild.’” صحيح - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (3/102))