Translation of the verse 21 from Surah Al-Inshiqaq : Number of verses 25 - - page 589 - Part 30.
And when the Quran is recited to them, they fall not prostrate,
And when the Qur'an is recited to them, they do not prostrate [to Allah]?
(84:21) and when the Qur'an is recited to them, they do not prostrate *12 themselves?
*12) "They do not fall prostrate": they do not bow down to God out of fear of Him. To perform a sajdah (prostration) here is confirmed by the practice of the Holy Prophet (upon whom be peace). lmam Malik, Muslim and Nasa'i have related a tradition concerning Hadrat Abu Huraira (may Allah be pleased with him>, saying that he recited this Surah in the Prayer and performing a sajdah here said: "The Holy Prophet (upon whom be peace) performed a sajdah at this point." Bukhari; Muslim, Abu Da'ud and Nasa'i have cited this statement of Abu Rafi`: "Hadrat Abu Huraira recited this Surah in the 'Isha' Prayer and performed a sajdah When I asked why he had done so, he replied: I prayed under the leadership of Abul Qasim (upon whom be Allah's peace) and he performed a sajdah here. Therefore, I will continue to perform this sajdah likewise as long as 1 live." Muslim, Abu Da'ud, Tirmidhi, Nasa'i, Ibn Majah and others have related another tradition saying that Hadrat Abu Huraira said: "We performed sajdah behind the Holy Messenger of Allah in this Surah and in Iqra' bi-ismi Rabbik-alladhi khalaq.
Source : Al-Inshiqaq Verse 21: And when the Qur'an is recited to them, they do not prostrate [to Allah]?