حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو مُعَاوِيَةَ، عَنِ الأَعْمَشِ، عَنْ أَبِي صَالِحٍ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ مَا اجْتَمَعَ قَوْمٌ فِي بَيْتٍ مِنْ بُيُوتِ اللَّهِ تَعَالَى يَتْلُونَ كِتَابَ اللَّهِ وَيَتَدَارَسُونَهُ بَيْنَهُمْ إِلاَّ نَزَلَتْ عَلَيْهِمُ السَّكِينَةُ وَغَشِيَتْهُمُ الرَّحْمَةُ وَحَفَّتْهُمُ الْمَلاَئِكَةُ وَذَكَرَهُمُ اللَّهُ فِيمَنْ عِنْدَهُ ‏"‏ ‏.‏

Abu Hurairah reported the Prophet (PBUH) as saying: No people get together in a house of the houses of Allah (i.e. a mosque), reciting the Book of Allah, and learning it together among themselves, but calmness (sakinah) comes down to 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. Translation Not Available

Book Ref: Sunan Abi Dawud Book 8 Hadith 1455
Web Ref:  Sunan Abi Dawud Book 8 Hadith 1450