Narrated Muhammad bin Ka'b Al-Qurazi:"I heard 'Abdullah bin Mas'ud saying: 'The Messenger of Allah (ﷺ) said: "[Whoever recites a letter] from Allah's Book, then he receives the reward from it, and the reward of ten the like of it. I do not say that Alif Lam Mim is a letter, but Alif is a letter, Lam is a letter and Mim is a letter

English translation · Jami' at-Tirmidhi