(3) بَابُ سَجْدَةِ {ص}
Narrated Ibn `Abbas:
The prostration of Sa`d is not a compulsory one but I saw the Prophet (ﷺ) prostrating while reciting it.
Reference: Sahih al-Bukhari 1069
In-book reference: Book 17, Hadith 3
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 19, Hadith 175