Sunan Ibn Majah, Chapter: The Book of the Sunnah

"The Messenger of Allah (saw) said: 'Whoever relieves a Muslim of some worldly distress, Allah will remove him of some of the distress of the Day of Resurrection, and whoever conceals (the faults of) a Muslim, Allah will conceal him (his faults) in this world and on the Day of Resurrection. And whoever relieves the burden from a destitute person, Allah will relieve him in this world and the next. Allah will help His slave so long as His slave helps his brother. Whoever follows a path in pursuit of 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 teaching it to one another, but the angels will surround them, tranquility will descend upon them, mercy will envelop them and Allah will mention them to those who are with Him. And whoever is hindered because of his bad deeds, his lineage will be of no avail to him.'" (Sahih)