question #1 Sahih Muslim 413b, Book 4, Hadith 91 : What is the significance of repeating the takbir in congregational prayer?

The Messenger of Allah (ﷺ) led the prayer and Abu Bakr was behind him. When the Messenger of Allah (ﷺ) recited the takbir, Abu Bakr also recited (it) in order to make it audible to us. And the rest of the hadith is like one transmitted by Laith.