Musnad Ahmad 31:152

Abu ‘Amir narrated to us, Fulayh narrated to us, from Sa‘id ibn al-Harith, who said: Abu Hurayrah complained [of illness]—or was absent—so Abu Sa‘id al-Khudri led us in prayer. He recited the takbir aloud when he began the prayer, when he bowed, when he said, "Allah hears those who praise Him," when he raised his head from prostration, when he prostrated, and when he stood up between the two rak‘ahs, until he finished his prayer in that manner. When he had prayed, it was said to him: "The people have differed regarding your prayer." So he went out and stood by the pulpit and said: "O people, by Allah, I do not care whether your prayer differed or did not differ; this is how I saw the Prophet, peace and blessings of Allah be upon him, praying."