Musnad Abi Ya'la 6572 — the Messenger of Allah ﷺ said: The imam

It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The imam is appointed only to be followed. So when he says the takbir, say the takbir; when he bows, bow; when he prostrates, prostrate; when he raises (his head from prostration), raise (yours); when he sits, sit; and when he stands, stand. The imam is a shield and he is the guarantor of the people's prayer. So if he offers the prayer at its proper time and fully observes its limits, then (the narrator said: I think he (peace and blessings be upon him) said:) he will have his own reward and the like of the rewards of those praying behind him, while nothing will be reduced from their reward. And the imam who does not pray on time and does not fulfil its limits will bear the burden of his own prayer as well as the burden of all those praying behind him, while no burden will be upon those praying behind him."