The Messenger of Allah ﷺ said, "Whoever relieves a believer of one of the hardships of this world, Allah will relieve him of one of the hardships of the Day of Resurrection. Whoever shields a Muslim, Allah will shield him in this world and the next. Whoever eases the burden of one in difficulty, Allah will ease his burden in this world and the next. Allah continues to aid His servant so long as the servant is aiding his brother. Whoever travels a path seeking knowledge, Allah will make easy for him a path to Paradise. No people gather in one of the houses of Allah, reciting the Book of Allah and studying it together, except that tranquility descends upon them, mercy envelops them, the angels surround them, and Allah mentions them to those near Him. And whoever is held back by his deeds, his lineage will not speed him forward."
حدثنا محمود بن غيلان حدثنا أبو أسامة حدثنا الأعمش عن أبي صالح
قال رسول الله ﷺ من نفس عن أخيه كربة من كرب الدنيا نفس الله عنه كربة من كرب يوم القيامة ومن ستر مسلما ستره الله في الدنيا والآخرة ومن يسر على معسر يسر الله عليه في الدنيا والآخرة والله في عون العبد ما كان العبد في عون أخيه ومن سلك طريقا يلتمس فيه علما سهل الله له طريقا إلى الجنة وما قعد قوم في مسجد يتلون كتاب الله ويتدارسونه بينهم إلا نزلت عليهم السكينة وغشيتهم الرحمة وحفتهم الملائكة ومن أبطأ به عمله لم يسرع به نسبه
Muslim also recorded it in the Book of Remembrance and Supplication, the chapter on the merit of gathering to recite the Quran and to engage in remembrance, Hadith 2699, from the hadith of Abu Usama with the same wording, and Amash explicitly stated that he heard it directly, according to Muslim's version.