Musnad Ahmad 769:47

'Affan narrated to us, 'Ubayd Allah ibn Iyad narrated to us, Iyad narrated to us, from 'Abd Allah ibn Sa'id, from 'Abd Allah ibn Abi Awfa, who said: A man from a distant place came while we were in the row behind the Messenger of Allah (peace and blessings of Allah be upon him). He entered the row, then said: "Allah is the Greatest, [much] greater, and glory be to Allah, morning and evening." The Muslims raised their heads and disapproved of the man, saying: "Who is it that raises his voice above the voice of the Messenger of Allah (peace and blessings of Allah be upon him)?" When the Prophet (peace and blessings of Allah be upon him) finished [the prayer], he said: "Who is this loud-voiced person?" He said: "It is I, O Messenger of Allah." He said: "By Allah, I saw your words ascending into the sky until a door of it was opened, and they entered through it."