The Book of Wills
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى التَّمِيمِيُّ، أَخْبَرَنَا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ، عَنْ مَالِكِ بْنِ مِغْوَلٍ، عَنْ طَلْحَةَ بْنِ مُصَرِّفٍ، قَالَ سَأَلْتُ عَبْدَ اللَّهِ بْنَ أَبِي أَوْفَى هَلْ أَوْصَى رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَالَ لاَ . قُلْتُ فَلِمَ كُتِبَ عَلَى الْمُسْلِمِينَ الْوَصِيَّةُ أَوْ فَلِمَ أُمِرُوا بِالْوَصِيَّةِ قَالَ أَوْصَى بِكِتَابِ اللَّهِ عَزَّ وَجَلَّ .Talha b. Musarrif reported:I asked 'Abdullah b. Abu Aufa whether Allah's Messenger (ﷺ) had made any will (in regard to his property). He said: NO. I said: Then why has making of will been made necessary for the Muslims, or why were they commanded to make will? Thereupon he said: He made the will according to the Book of Allah, the Exalted and Majestic
From Sahih Muslim, whose reports the scholars accept as authentic.