Rasulullah (sallallahu alayhi wasallam)
said: “Verily, I find in the Kitaab of Allah(The Qur’aan Majeed) a Surah of 30Verses. Whoever recites it at the timeof going to sleep, Allah Ta’ala will record for him (or her) 30 deeds ofvirtue, efface 30 of his sins and elevate him by 30 ranks.
Allah will send for him an Angel who will cover him (the reciter of the Surah) with his wings,and protect him from every (evil/harmful) thing until he wakes up (in the
morning). That Surah will fight on hisbehalf in the Qabr (protecting him from the torments of the grave)
That is Surah Mulk