Mu’adh b. Jabal would pray along the prophet (ﷺ), then go and lead his people in prayer.

the Imam is appointed only to be followed ; so when he prays standing, pray standing, and when he bows, bow; when he raises himself, raise yourselves; when he says “Allah listen to him who praises Him”, “Our Lord ! to Thee be the praise”: and when he prays sitting all of you pray sitting.

The Messenger of Allah (ﷺ) rode a horse in Medina. It threw him off at the root of a date-palm. His foot was injured. We visited him to inquire about his illness. We found him praying sitting in the apartment of Aisha. We, therefore, stood, (praying) behind him. He kept silent.

We again visited him to inquire about his illness. He offered the obligatory prayer sitting. We, therefore, stood (praying) behind him; he made a sign to us and we sat down. When he finished the prayer, he said: When the imam prays sitting, pray sitting; and when the imam prays standing, pray standing, and do not act as the people of Persia used to act with their chiefs (i.e. the people stood and they were sitting).

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.

The Prophet (ﷺ) said: The imam is appointed only to be followed. This version adds: When he recites (the Qur'an), 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).

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.