Waitha quria alquranu faistamiAAoo lahu waansitoo laAAallakum turhamoona
So, when the Quran is recited, listen to it, and be silent that you may receive mercy. (i.e. during the compulsory congregational prayers when the Imam (of a mosque) is leading the prayer (except Soorat Al-Fatiha), and also when he is delivering the Friday-prayer Khutbah).
Surah Al- Araf, The Heights, Ayah 204