Bismillah. AssalaamuAlaikum The difference between a Caliph and a King: Umar said: “By Allah, I do not know if I am a caliph or a king. If I am a king this is a serious matter.” Someone said to him: “There is a difference between them. A caliph does not take anything except rightfully, and he does not five anything except rightfully, and you – praise be to Allah – are like that. A king oppresses the people, taking from one and giving to another.” And Umar fell silent. [Ash-Shaykan Abu Bakr as-Siddeeq wa Umar ibn al-Khattab min Riqayat al-Baladhuri p.257.] According to another report, Umar asked Salman al-Farisi: “Am I a king or a caliph?” Salman said: “ If you collect from the land a dirham, or less or more, and put it where it does not belong, then you are a king and not a caliph.” And Umar wept. [Ibid] From - Umar ibn Al-Khattab His Life & Times by Dr. Ali Muhammad as-Sallabi. p. 181 Peace.