Riyad us Saliheen: Hadith 1015

I heard the Messenger of Allah (ﷺ) 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].