Translation
(17) Prostration During Recital of Qur'an
كتاب سجود القرآن
(4) Chapter: The prostration in An-Najm (No. 53)
(4) باب سَجْدَةِ النَّجْمِ
Sahih al-Bukhari 1070 

Narrated `Abdullah bin Mas`ud:

The Prophet (ﷺ) recited Surat-an-Najm (53) and prostrated while reciting it and all the people prostrated and a man amongst the people took a handful of stones or earth and raised it to his face and said, "This is sufficient for me. Later on I saw him killed as a non-believer."

حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ أَبِي إِسْحَاقَ، عَنِ الأَسْوَدِ، عَنْ عَبْدِ اللَّهِ ـ رضى الله عنه ـ أَنَّ النَّبِيَّ صلى الله عليه وسلم قَرَأَ سُورَةَ النَّجْمِ فَسَجَدَ بِهَا، فَمَا بَقِيَ أَحَدٌ مِنَ الْقَوْمِ إِلاَّ سَجَدَ، فَأَخَذَ رَجُلٌ مِنَ الْقَوْمِ كَفًّا مِنْ حَصًى أَوْ تُرَابٍ، فَرَفَعَهُ إِلَى وَجْهِهِ وَقَالَ يَكْفِينِي هَذَا، فَلَقَدْ رَأَيْتُهُ بَعْدُ قُتِلَ كَافِرًا‏.‏
Reference : Sahih al-Bukhari 1070
In-book reference : Book 17, Hadith 4
USC-MSA web (English) reference : Vol. 2, Book 19, Hadith 176
  (deprecated numbering scheme)