There is a Hadith narrated by Imam al-Hakim in which the Holy Prophet peace be upon him said that “Surah al Mulk prevents from the punishment in the grave.” Imam Hakim also narrated that Abdullah bin Mas‘ud said that, The Holy Prophet peace be upon him sad that: “when is person is buried in his grave, he will be approached from his feet and the feet will say that you cannot harm for what is in my heart, the person used to stand on me and read this Surah Then the person will be approached from his chest, and the chest will say that you don’t have any right to harm for what is in my heart is he used to recite Surah al-Mulk. Then the man will be approached from the head, and the head will say that you don’t have any way to harm for what is in the heart as the man used to recite by me.” Then Abdullah bin Mas‘ud said that this Surah prevents from the punishment in the grave. Based on these –and many other- Ahadith, the Muslim scholars hope that the people who believe and read Surah al-Mulk regularly will be saved from the punishment, and they will deserve the mercy and pleasure of Allah Almighty.
There is a Hadith which says that Prophet peace be upon him used to recite Surah al-Mulk every night. Abdullah bin Mas‘ud narrates that “whoever recites Surah al-Mulk every night, Allah will prevent the punishment of grave by this Surah”. According to another tradition, when a person reads Surah Al-Mulk before sleeping, an angel comes down to protect him because he is not able to protect himself due to sleep. Therefore Muslims need to bring the recitation of Surah Mulk explanation and lessons in their routine, and for that, they should memorize the Surah so that they will be at ease to recite the Surah whenever they need to