Abu Hurayrah (may Allah be pleased with him) reported: The Prophet (may Allah's peace and blessings be upon him) said: "The most despicable name in the sight of Allah is that of a man named the King of kings. There is no king but Allah." In another version: "The most wretched and most malicious person in the sight of Allah on the Day of Resurrection and the one who will incur His wrath most will be the person who used to be called the King of kings, for there is no king but Allah." Sufyān said: “Like Shahenshah (meaning: the King of kings).”
عن أبي هريرة -رضي الله عنه- عن النبي -صلى الله عليه وسلم- قال: «إن أَخْنَعَ اسم عند الله رجل تسمى ملك الأملاك، لا مالك إلا الله». وفي رواية: «أَغْيَظُ رجل على الله يوم القيامة، وأخبثه وأَغْيَظُه عليه، رجل كان يسمى ملك الأملاك، لا مَلِكَ إلا الله». قال سفيان: «مثل شَاهَانْ شَاهْ»، وقال أحمد بن حنبل: سألت أبا عمرو عن أَخْنَع؟ فقال: «أَوْضَع».
شرح الحديث :
The Messenger (may Allah's peace and blessings be upon him) informs us in this Hadīth that the most despicable and meanest of people in the sight of Allah, the Almighty, is someone who has a name that projects meanings of glorification and pride that befit none but Allah, the Exalted, such as the King of kings. This signifies rivalry with Allah. A person called by such a name claims to be or is claimed to be a rival to Allah, the Almighty. Therefore, he is regarded as the most despicable and most malicious person in the sight of Allah or it is probably meant that he is one of the most hated of people. The Prophet (may Allah's peace and blessings be upon him) makes it clear that there is no true King for this universe, including all its rulers and ruled, but the Almighty Allah. It is hoped this Hadīth will be a reminder to those who call people by certain names or titles without considering their meanings and implications, lest they would be subject to the evil consequence this Hadīth warns against. May Allah help all of us!