Sunan an-Nasa'i 798
سنن النسائي#798SahihIt 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
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih Muslim
In-book reference: 10:22