"The Prophet was in front of Abu Bakr and he prayed sitting down, and Abu Bakr was leading the people in prayer, and the people were behind Abu Bakr."
Sunan an-Nasa'i Book 10, Hadith 21
← Previous Hadith (Another chain) from Abu Nadrah (from Abu Sa'eed) with similar narration.

Sunan an-Nasa'i Book 10, Hadith 20 Next Hadith → "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."

Sunan an-Nasa'i Book 10, Hadith 22