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.
Hadith ReferenceSunan Abi Dawud / Prayer (Kitab Al-Salat): Prostration while reciting the Quran / Hadith: 1409
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:صحيح بخاري (1069)