Abu Hurairah (May Allah be pleased with him) said:
The Prophet (ﷺ) said, "The most disgraceful man near Allah is a man who calls himself (or likes others to call him) Malikul-Amlak (i.e., king of kings)."[Al-Bukhari and Muslim].
App reference: Book 18, Hadith 214
Arabic/English book reference: Book 18, Hadith 1724