Bulugh al-Maram 351a — The Book of Prayer

Abu Hurairah Narrated from:

The Prophet (ﷺ) led us in two Rak'at of one of the two, Zuhr or 'Asr prayers, and said the Taslim (salutation). He then got up and went towards a piece of wood which was at the front part of the mosque and placed his hands upon it. Abu Bakr and 'Umar were among the people, but they were afraid to speak to him. Then some of the hasty type of people came out and said, "Has the Salat (prayer) been shortened?"A man whom the Prophet (ﷺ) called Dhul Yadain (the long armed) asked: "Have you forgotten, O Allah's Messenger or has the prayer been shortened?" He said, "I have neither forgotten nor has it been shortened." He said, "Indeed you have forgotten."He [the Prophet (ﷺ)] then prayed the remaining two Rak'at, then said the Taslim (salutation). He then uttered the Takbir and prostrated similar to his normal prostration or longer, then raised up his head and uttered the Takbir. He then prostrated and uttered the Takbir, and the prostration was similar to his normal prostration or longer. He then raised his head and uttered the Takbir.[Agreed upon, and it is al-Bukhari's wording].