Sunan an-Nasa'i 798
سنن النسائي#798Sahihأَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ فَضَالَةَ بْنِ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا يَحْيَى، - يَعْنِي ابْنَ يَحْيَى - قَالَ حَدَّثَنَا حُمَيْدُ بْنُ عَبْدِ الرَّحْمَنِ بْنِ حُمَيْدٍ الرُّؤَاسِيُّ، عَنْ أَبِيهِ، عَنْ أَبِي الزُّبَيْرِ، عَنْ جَابِرٍ، قَالَ صَلَّى بِنَا رَسُولُ اللَّهِ صلى الله عليه وسلم الظُّهْرَ وَأَبُو بَكْرٍ خَلْفَهُ فَإِذَا كَبَّرَ رَسُولُ اللَّهِ صلى الله عليه وسلم كَبَّرَ أَبُو بَكْرٍ يُسْمِعُنَا .
It was narrated that Jabir said:"The Messenger of Allah (ﷺ) led us in Zuhr prayer and Abu Bakr was behind him. When the Messenger of Allah (ﷺ) said the Takbir, Abu Bakr said the Takbir so that the people could hear
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:
In-book reference: 10:22