Sahih al-Bukhari 1229

Hafs ibn 'Umar narrated to us; Yazid ibn Ibrahim narrated to us, from Muhammad, from Abu Hurayrah (may Allah be pleased with him), who said: The Prophet (ﷺ) prayed one of the two afternoon prayers—Muhammad said: ‘I think it was most likely 'Asr’—two rak'ahs, then said the taslim. He stood by a wooden post at the front of the mosque and placed his hand on it. Abu Bakr and 'Umar (may Allah be pleased with them both) were there, but they were reluctant to speak to him. The people in a hurry went out, saying: ‘Has the prayer been shortened?’ A man whom the Prophet (ﷺ) called Dhu al-Yadayn said: ‘Did you forget, or was it shortened?’ He said: ‘I did not forget, and it was not shortened.’ The man said: ‘Indeed, you forgot.’ The Prophet prayed two rak'ahs, said the taslim, then said the takbir and prostrated like his usual prostration or longer. Then he raised his head and said the takbir, lowered his head and said the takbir, and prostrated like his usual prostration or longer. Then he raised his head and said the takbir.