Sahih al-Bukhari 404
صحيح البخاري#404Sahihحَدَّثَنَا مُسَدَّدٌ، قَالَ حَدَّثَنَا يَحْيَى، عَنْ شُعْبَةَ، عَنِ الْحَكَمِ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، عَنْ عَبْدِ اللَّهِ، قَالَ صَلَّى النَّبِيُّ صلى الله عليه وسلم الظُّهْرَ خَمْسًا فَقَالُوا أَزِيدَ فِي الصَّلاَةِ قَالَ " وَمَا ذَاكَ ". قَالُوا صَلَّيْتَ خَمْسًا. فَثَنَى رِجْلَيْهِ وَسَجَدَ سَجْدَتَيْنِ.
Narrated `Abdullah:"Once the Prophet (ﷺ) offered five rak`at in Zuhr prayer. He was asked, "Is there an increase in the prayer?" The Prophet (ﷺ) said, "And what is it?" They said, "You have prayed five rak`at.' So he bent his legs and performed two prostrations (of Sahu)
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: 8:56