(5) باب السُّجُودِ فِي { ص }
Narrated Ibn 'Abbas:
A prostration when reciting Sad is not one of those which are divinely commanded, but I have seen Messenger of Allah (ﷺ) prostrate himself. (ID)
Reference (ID): Sunan Abi Dawud 1409 (ID)
In-book reference (ID): Book 7, Hadith 9 (ID)
English translation (ID): Book 7, Hadith 1404 (ID)