Sahih Muslim Book 4, Hadith 124
This hadith is narrated by Anas with another chain of transmitters, and in the hadith transmitted by Jarir there is no mention of" turning (faces)".
The Messenger of Allah (ﷺ) one day led us in the prayer. and when he completed the Prayer he turned his face towards us and said: 0 People, I am your Imam, so do not precede me in bowing and prostration and in standing and turning (faces, i. e. In pronouncing salutation), for I see you in front of me and behind me, and then said: By Him in Whose hand Is the life of Muhammad, if you could see what I see, you would have laughed little and wept much more. They said: What did you see, Messenger of Allah? He replied: (I saw) Paradise and Hell.
The Messenger of Allah (ﷺ) said: Does the man who lifts his head ahead of the Imam (from prostration) not fear that Allah may change his head into the head of an ass?