Sunan Ibn Majah
3786
Sahih+3

It was narrated from Abu Hurairah that the Prophet (ﷺ) said:"There is a surah in the Qur'an, with thirty verses, which will intercede for its companion (the one who recites it) until he is forgiven: Tabarakal-ladhi bi yadihil mulk (Blessed is He in Whose Hand is the Dominion)

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi