Sahih Muslim
The Book on General Behaviour (Kitab Al-Adab)
Book Number: 025 / Hadith Number: 5339
Abu Huraira reported from Allah's Messenger (may peace be upon him) so many ahadith and one of them was this that Allah's Messenger (may peace be upon him) said: The most wretched person in the sight of Allah on the Day of Resurrection and the worst person and target of His wrath would of the person who is called Malik al-Amlak (the King of Kings) for there is no king but Allah.