The Messenger of Allah (ﷺ) finished praying two rak'ahs,and Dhul-Yadain said to him: "Has the prayer been shortened or did you forget, O Messenger of Allah?" The Messenger of Allah (ﷺ) said: "Is Dhul-Yadain speaking the truth?" The people said: "Yes." So the Messenger of Allah (ﷺ) stood up and prayed two, then he said the takbir and prostrated as usual or longer than that. Then he raised his head, then he prostrated as usual or longer than that, then he sat up."
Hadith Text
The Messenger of Allah (ﷺ) finished praying two rak'ahs, and Dhul-Yadain said to him: "Has the prayer been shortened or did you forget, O Messenger of Allah?" The Messenger of Allah (ﷺ) said: "Is Dhul-Yadain speaking the truth?" The people said: "Yes." So the Messenger of Allah (ﷺ) stood up and prayed two, then he said the takbir and prostrated as usual or longer than that. Then he raised his head, then he prostrated as usual or longer than that, then he sat up.
Source Reference
The Book of Forgetfulness (In Prayer)
Sunan an-Nasa'i
Sunan an-Nasa'i 1225
Scholarly Commentary
This hadith demonstrates the proper procedure for making up missed rak'ahs in prayer due to forgetfulness. The Prophet's (ﷺ) inquiry "Is Dhul-Yadain speaking the truth?" shows the importance of verification when reminded during prayer. His completion of the remaining two rak'ahs followed by the prostration of forgetfulness (sujud al-sahw) establishes the sunnah for such situations.
The prostration being "as usual or longer" indicates flexibility in its duration. This incident also shows the permissibility of speaking during prayer when necessary to correct an error, and the obligation to complete what was missed rather than restarting the prayer.
Dhul-Yadain's courage in respectfully correcting the Prophet (ﷺ) teaches us that religious correction should be given with proper etiquette when one is certain of an error, even if it involves someone of higher status.