Abu Musa led us in prayer. When he was in the sitting position, a man among the congregation entered and said, "Prayer has been linked with righteousness and zakat."When Abu Musa concluded the prayer with the salam, he turned to the people and asked, "Which of you spoke those words?"The people remained silent.He said, "Hittan, perhaps it was you who said it?"Hittan replied, "No. I was afraid you would rebuke me for it."Abu Musa then said, "The Messenger of Allah ﷺ used to teach us our prayer and our practice. He said, 'The imam is appointed only to be followed. So when he says the takbir, say the takbir. When he recites 'not of those who have incurred wrath, nor of those who have gone astray' [Fatihah 1:7], say Ameen, and Allah will respond to you. When he bows, bow. When he rises and says, "Allah hears whoever praises Him," say, "Our Lord, to You belongs all praise," and Allah will hear you. When he prostrates, prostrate. When he rises, rise. For the imam prostrates before you and rises before you.' The Messenger of Allah ﷺ said, 'That makes up for this.'"
أخبرنا مؤمل بن هشام قال حدثنا إسمعيل ابن علية عن سعيد عن قتادة عن يونس بن جبير
صلى بنا أبو موسى فلما كان في القعدة دخل رجل من القوم فقال أقرت الصلاة بالبر والزكاة فلما سلم أبو موسى أقبل على القوم فقال أيكم القائل هذه الكلمة فأرم القوم قال يا حطان لعلك قلتها قال لا وقد خشيت أن تبكعني بها فقال إن رسول الله ﷺ كان يعلمنا صلاتنا وسنتنا فقال إنما الإمام ليؤتم به فإذا كبر فكبروا وإذا قال {غير المغضوب عليهم ولا الضالين} فقولوا آمين يجبكم الله وإذا ركع فاركعوا وإذا رفع فقال سمع الله لمن حمده فقولوا ربنا لك الحمد يسمع الله لكم وإذا سجد فاسجدوا وإذا رفع فارفعوا فإن الإمام يسجد قبلكم ويرفع قبلكم قال رسول الله ﷺ فتلك بتلك
Muslim narrated it, Prayer, chapter on the tashahhud in prayer, hadith no. 404, from the hadith of Saeed bin Abu Aruba, with the same wording, and it is also in Kubra, hadith no. 904.