Majma al-Zawaid — Hadith 11660

Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: This Qur'an is the banquet of Allah Almighty, so acquire knowledge from His banquet as much as you can. This Qur'an is the rope of Allah Almighty which He has commanded, it is the clear light and the beneficial cure. It is a protection for whoever seeks protection through it and salvation for whoever holds fast to it. It does not become crooked so that it needs to be straightened, it does not go astray so that it needs to be set right, its wonders will never come to an end, and it does not wear out from being read over and over. Recite it, for Allah Almighty will give you ten good deeds for every single letter of it. I do not say to you that "Alif Lam Mim" is one letter; rather "Alif" is a letter, "Lam" is a letter and "Mim" is a letter.
Imam al-Tabarani recorded it; its chain contains a narrator, Muslim bin Ibrahim al-Hajari, who is matruk (abandoned).