Hittan ibn Abdullah ar-Ruqashi said: Abu Musa al-Ash'ari led us in prayer, and when he sat at the end of his prayer, a man from the people said, 'Prayer has been established by righteousness and charity.' When Abu Musa finished and turned to face the people, he said, 'Which of you is the speaker of such and such a word?' The people remained silent. He asked again, 'Which of you is the speaker of such and such a word?' The people remained silent. Then he said, 'Perhaps you, Hittan, uttered it?' He replied, 'I did not utter it, and I feared that you might rebuke me for it.' A man from the people said, 'I uttered it, and I intended nothing by it except good.'
Abu Musa said, 'Do you not know what you say in your prayer? Verily, the Messenger of Allah (ﷺ) addressed us, taught us, explained to us our tradition, and taught us our prayer, saying: "When you pray, straighten your rows, and then let one of you lead you. When he says the takbir, say the takbir, and when he recites
not of those upon whom is anger, nor of those who straysay 'Amin' and Allah will answer you. When he says the takbir and bows, say the takbir and bow, for the imam bows before you and raises his head before you."'
The Messenger of Allah (ﷺ) said, "That is in lieu of that. And when he says, 'Allah listens to the one who praises Him,' say, 'O Allah, our Lord, to You be praise,' and Allah will listen to you, for Allah the Exalted said upon the tongue of His Prophet (ﷺ): 'Allah listens to the one who praises Him.' And when he says the takbir and prostrates, say the takbir and prostrate, for the imam prostrates before you and raises his head before you."
The Messenger of Allah (ﷺ) said, "That is in lieu of that. And when you are sitting, let the first thing any of you says be: "All greetings, all good things, and all prayers are for Allah. Peace be upon you, O Prophet, and the mercy of Allah and His blessings. Peace be upon us and upon the righteous servants of Allah. I bear witness that there is no god but Allah, and I bear witness that Muhammad is His servant and His messenger."
Ahmad did not mention "and His blessings" nor did he say "and I bear witness"; and he said "and that Muhammad".