I offered the `Isha' prayer behind Abu Huraira and he recited Idhas-Sama' Un-Shaqqat, and prostrated. I said, "What is this?" Abu Huraira said, "I prostrated behind Abul-Qasim and I will do the same till I meet him."
Prostration During Recital of Qur'an
Sahih al-Bukhari 1078
Hadith Commentary
This narration demonstrates the established Sunnah of performing prostration when reciting or hearing verses of prostration (as-sajdāt) from the Qur'an. The companion's action follows the prophetic practice of Abul-Qasim (the Prophet Muhammad ﷺ).
Abu Huraira's response "I will do the same till I meet him" indicates the perpetual obligation of following the Prophet's Sunnah. The prostration in Surah al-Inshiqaq (Chapter 84) is among the fifteen agreed-upon places of prostration in the Qur'an.
Scholars hold that performing these prostrations is sunnah mu'akkadah (emphasized Sunnah) for both reciter and listener. The timing is immediately after reciting the verse, whether during prayer or outside it, as demonstrated here during Isha prayer.
Legal Ruling
The Hanafi and Maliki schools consider it wajib (obligatory), while Shafi'i and Hanbali schools regard it as sunnah mu'akkadah. All agree it's a established practice from the Prophet ﷺ that Muslims should preserve.