(4) باب مَنْ لَمْ يَتَشَهَّدْ فِي سَجْدَتَىِ السَّهْوِ
Narrated Abu Huraira.:
Once Allah's Messenger (ﷺ) offered two rak`at and finished his prayer. So Dhul-Yadain asked him, "Has the prayer been reduced or have you forgotten?" Allah's Messenger (ﷺ) said, "Has Dhul-Yadain spoken the truth?" The people replied in the affirmative. Then Allah's Messenger (ﷺ) stood up and offered the remaining two rak`at and performed Taslim, and then said Takbir and performed two prostrations like his usual prostrations, or a bit longer, and then got up.
Reference: Sahih al-Bukhari 1228
In-book reference: Book 22, Hadith 5
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 22, Hadith 319