Narrated Abu Huraira: Allah's Apostle 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)."
— Sahih Bukhari, Volume 8, Book 73: Good Manners and Form (Al-Adab), Hadith #224
Narrated Abu Huraira: Allah's Apostle 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)."
This hadith is from the book of Good Manners and Form (Al-Adab) in Sahih Bukhari, compiled by Imam al-Bukhari. It is hadith number 224 in book 73 of volume 8.
This hadith is referenced in the following topics: Humility.