كتاب السهو
Read the English translation first, with the original Arabic directly underneath.
It was narrated that Abu Hurairah said:
"The Messenger of Allah (ﷺ) forgot and said the taslim after two rak'ahs. Dhul-Shimalain said to him: 'Has the prayer been shortened or did you forget, O Messenger of Allah (ﷺ)?' The Messenger of Allah (ﷺ) said: 'Is Dhul-Yadain speaking the truth?' They said: "Yes." So the Messenger of Allah (ﷺ) stood up and completed the prayer."
أَصَدَقَ ذُو الْيَدَيْنِ