Sahih al-Bukhari 2738
صحيح البخاري#2738Sahihحَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ـ رضى الله عنهما ـ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " مَا حَقُّ امْرِئٍ مُسْلِمٍ لَهُ شَىْءٌ، يُوصِي فِيهِ يَبِيتُ لَيْلَتَيْنِ، إِلاَّ وَوَصِيَّتُهُ مَكْتُوبَةٌ عِنْدَهُ ". تَابَعَهُ مُحَمَّدُ بْنُ مُسْلِمٍ عَنْ عَمْرٍو عَنِ ابْنِ عُمَرَ عَنِ النَّبِيِّ صلى الله عليه وسلم.
Narrated `Abdullah bin `Umar:Allah's Messenger (ﷺ) said, "It is not permissible for any Muslim who has something to will to stay for two nights without having his last will and testament written and kept ready with him
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 55:1