كتاب الأذكار
16
The Book of the Remembrance of Allah
Abu Hurairah and Abu Sa'id Al-Khudri (May Allah be pleased with them) reported:
The Messenger of Allah (ﷺ) said, "When a group of people assemble for the remembrance of Allah, the angels surround them (with their wings), (Allah's) mercy envelops them, Sakinah, or tranquillity descends upon them and Allah makes a mention of them before those who are near Him."

[Muslim].

وعنه وعن أبي سعيد رضي الله عنهما قالا‏:‏ قال رسول الله صلى الله عليه وسلم‏:‏ ‏ "‏لا يقعد قوم يذكرون الله عز وجل إلا حفتهم الملائكة، وغشيتهم الرحمة ونزلت عليهم السكينة، وذكرهم الله فيمن عنده‏"‏ ‏(‏‏(‏رواه مسلم‏)‏‏)‏‏.‏
Sunnah.com reference : Book 16, Hadith 41
Arabic/English book reference : Book 16, Hadith 1448