Sunan Ibn Majah, Chapter: The Chapters of Establishing the Prayer and the Sunnah Regarding Them

that the Messenger of Allah (saw) forgot and said the Taslim after two Rakah. A man who was called Dhul-Yadain said to him: 'O Messenger of Allah (saw), has the prayer been shortened or did you forget?' He said: 'It has not been shortened and I did forget.' He said: 'But you prayed two Rakah.' He said: 'Is what Dhul-Yadain says true?' They said: 'Yes.' So he went forward and performed two Rakah and said the Salam, then he prostrated twice for prostrations of forgetfulness. Hasan