Sahih al-Bukhari 3736
صحيح البخاري#3736Sahihوَقَالَ نُعَيْمٌ عَنِ ابْنِ الْمُبَارَكِ، أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، أَخْبَرَنِي مَوْلًى، لأُسَامَةَ بْنِ زَيْدٍ. أَنَّ الْحَجَّاجَ بْنَ أَيْمَنَ ابْنِ أُمِّ أَيْمَنَ،، وَكَانَ، أَيْمَنُ ابْنُ أُمِّ أَيْمَنَ أَخَا أُسَامَةَ لأُمِّهِ، وَهْوَ رَجُلٌ مِنَ الأَنْصَارِ، فَرَآهُ ابْنُ عُمَرَ لَمْ يُتِمَّ رُكُوعَهُ وَلاَ سُجُودَهُ فَقَالَ أَعِدْ.
The freed slave of Usama bin Zaid said, "Al-Hajjaj bin Aiman bin Um Aiman and Aiman Ibn Um Aiman was Usama's brother from the maternal side, and he was one of the Ansar. He was seen by Ibn 'Umar not performing his bowing and prostrations in a perfect manner. So Ibn 'Umar told him to repeat his prayer
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: 62:83