Sahih Muslim 573 a

Ibn Sirin reported Abu Huraira as saying: The Messenger of Allah (ﷺ) led us in one of the two evening prayers, Zuhr or `Asr, and gave salutations after two rak`ahs and going towards a piece of wood which was placed to the direction of the Qibla in the mosque, leaned on it looking as if he were angry. Abu Bakr and `Umar were among the people and they were too afraid to speak to him and the people came out in haste (saying): The prayer has been shortened. But among them was a man called Dhul-Yadain who said: Messenger of Allah, has the prayer been shortened or have you forgotten? The Messenger of Allah (ﷺ) looked to the right and left and said: What was Dhul-Yadain saying? They said: He is right. You (the Holy Prophet) offered but two rak`ahs. He offered two (more) rak`ahs and gave salutation, then said takbir and prostrated and lifted (his head) and then said takbir and prostrated, then said takbir and lifted (his head). He (the narrator) says: It has been reported to me by `Imran b. Husain that he said: He (then) gave salutation.