Abu Dawud Book 2, Hadith Number 1450.
Chapter : On the reward of reciting the quran.
Narated By Abu Hurairah : The Prophet (PBUH) said: No people get together in a house of the houses of Allah (i.e. the mosque), reciting the Book of Allah, and learning it together among themselves, but calmness (sakinah) comes down on them, (Divine) mercy covers them (from above), and the angels surround them, and Allah makes a mention of them among those who are with him.