Sahih al-Bukhari 6205
صحيح البخاري#6205SahihNarrated Abu Huraira:Allah's Messenger (ﷺ) said, "The most awful name in Allah's sight on the Day of Resurrection, will be (that of) a man calling himself Malik Al-Amlak (the king of kings)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 78:229