It was narrated from Hittan bin 'Abdullah that Al-Ash'ari said

"The Messenger of Allah (ﷺ) addressed us and taught us our Sunnahs and our prayer. He said: 'When you stand for the prayer, make your rows straight, then let one of you lead the others. When he says the takbir, then say the takbir; when he says : "Wa lad-dallin" then say "Amin" and Allah ﷻ will answer you. Then when he says the takbir and bows, then say the takbir and bow, for the Imam bows before you and stands up before you.' The Prophet (ﷺ) of Allah (ﷺ) said: "This makes up for that. When he says: 'Sami' Allahu liman hamidah (Allah hears the one who praises Him),' say: 'Allahumma, Rabbana wa lakal-hamd (O Allah, our Lord, to You be praise),' Allah will hear you, for indeed Allah ﷻ, the Mighty and Sublime, has said on the tongue of His Prophet: "Allah hears the one who praises Him." Then when he says the takbir and prostrates, say the takbir and prostrate, for the Imam prostrates before you and rises before you.' The Prophet (ﷺ) of Allah (ﷺ) said: 'This makes up for that. Then when you are sitting, let the following be among what one of you says: At-tahiyyatu lillahi wasalawatu wat-tayibaat, as-salamu 'alaika ayah-Nabiyyu wa rahmatAllahi wa baraktuhu. As-salamu 'alaina a 'ala ibad illahis-salihin, ashadu an la ilaha ill Allah, wa ashhadu anna Muhammad an 'abduhu wa rasuluhu. (All compliments, prayers and pure words are due to Allah. Peace be upon you O Prophet, and the mercy of Allah and His blessings. Peace be upon us and upon the righteous slaves of Allah. I bear witness that that none has the right to be worshipped except Allah, and I bear witness that Muhammad is His slave and messenger.)"