كتاب السهو
Read the English translation first, with the original Arabic directly underneath.
It was narrated that Imran bin Husain said:
"The Messenger of Allah (ﷺ) said the salam after three rak'ahs of 'Asr, then he entered his house. A man called Al-Khibaq stood up and said: 'Has the prayer been shortened, O Messenger of Allah?' He came out angry, dragging his upper garment and said: 'Is he speaking the truth?' They said: 'Yes.' So he stood and prayed that rak'ah, then he said the salam, then prostrated twice, then he said the salam (again)."
أَصَدَقَ