Sahih al-Bukhari 4699
صحيح البخاري#4699Sahihحَدَّثَنَا أَبُو الْوَلِيدِ، حَدَّثَنَا شُعْبَةُ، قَالَ أَخْبَرَنِي عَلْقَمَةُ بْنُ مَرْثَدٍ، قَالَ سَمِعْتُ سَعْدَ بْنَ عُبَيْدَةَ، عَنِ الْبَرَاءِ بْنِ عَازِبٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " الْمُسْلِمُ إِذَا سُئِلَ فِي الْقَبْرِ يَشْهَدُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَنَّ مُحَمَّدًا رَسُولُ اللَّهِ، فَذَلِكَ قَوْلُهُ {يُثَبِّتُ اللَّهُ الَّذِينَ آمَنُوا بِالْقَوْلِ الثَّابِتِ فِي الْحَيَاةِ الدُّنْيَا وَفِي الآخِرَةِ}"
Narrated Al-Bara bin Azib:Allah's Messenger (ﷺ) said, "When a Muslim is questioned in his grave, he will testify that none has the right to be worshipped but Allah and that Muhammad is Allah's Messenger (ﷺ), and that is what is meant by Allah's Statement:-- "Allah will keep firm those who believe with a Word that stands firm in this world and in the Hereafter
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: 65:221