Sahih Bukhari
Prostration During Recital of Quran
Volume: 002 / Book Number: 019 / Hadith Number: 182
Narrated Ibn 'Umar,
When the Prophet recited Surat As-Sajda and we were with him, he would prostrate and we also would prostrate with him and some of us (because of the heavy rush) would not find a place (for our foreheads) to prostrate on.