The Virtues of Reciting Surah Al Mulk Every Night...
‘Abdallah ibn Mas'ood (radhiAllahu 'anhu) said:
“Whoever reads 'al-Mulk’ every night, Allah will protect him from the torment of the grave. At the time of the Messenger of Allah (sallAllahu 'alayhi wa sallam), we used to call it al-mani'ah (that which protects). In the Book of Allah, there is a chapter [and] whoever recites it every night has done very well.”
[Sahih at-Targhib wat-Tarhib, no. 1475]
Imam Ahmad recorded from Abu Hurayrah (may Allah be pleased with him) that Allah’s Messenger (sallAllahu 'alayhi wa sallam) said,
“Verily, there is a chapter in the Qur'an which contains thirty Ayat that will intercede on behalf of its reciter until he is forgiven. (It is): 'Blessed be He in Whose Hand is the dominion.’”
[This Hadith was collected by At-Tirmidhi and the four Sunan Compilers. At-Tirmidhi said concerning it, “This is a Hasan Hadith.”]
He (sallAllahu 'alayhi wa sallam) used to recite Surah As-Sajdah and Surah Al-Mulk before sleeping.
[Reference: At-Tirmithi, An-Nasa'i. See also Al-Albani, Sahihul-Jami ’ As-Saghir 4/255]
Abu Hurairah (may Allah be pleased with him) reported: I heard the Messenger of Allah (sallAllahu 'alayhi wasallam) saying,
“There is a Surah in the Qur'an which contains thirty Ayat which kept interceding for a man until his sins are forgiven. This Surah is 'Blessed is He in Whose Hand is the dominion.’ (Surat Al-Mulk 67).”
[At-Tirmidhi and Abu Dawud]