The Prophet (ﷺ) said: The imam is appointed only to be followed. This version adds: When he recites (the Quran), keep silent."

Abu Dawud said: The addition of the words "When he recites, keep silent" in this version are not guarded. The misunderstanding, according to us, is on the part of Abu Khalid (a narrator).
Sunan Abi Dawud Book 2, Hadith 214
← Previous Hadith The Prophet (ﷺ) said: The imam is appointed only to be followed; when he says "Allah is most great," say "Allah is most great" and do not say "Allah is most great" until he says "Allah is most great." When he bows; bow; and do not bow until he bows. And when he says "Allah listens to him who praise Him," say "O Allah, our Lord, to Thee be the praise."

The version recorded by Muslim goes: "And to Thee be the praise: And when he prostrate; and do not prostrate until he prostrates. When he prays standing, pray standing, and when he prays sitting, all of you pray sitting.

Abu Dawud said: The words "O Allah, our Lord, to You be the praise" reported by Sulaiman were explained to me by some of our companions.

Sunan Abi Dawud Book 2, Hadith 213 Next Hadith → The IMAM is appointed only to be followed; so when he prays standing. Pray standing ; and when he raises himself, raise yourself: and when he prays sitting. Pray sitting.

Sunan Abi Dawud Book 2, Hadith 215