What is the ruling on saying: "And you, O Muslims, are the vicegerents of Allah on His earth"?

This expression is incorrect because Allah Almighty is the Creator and Owner of everything, and He has not been absent from His creation to appoint a successor for Him. Rather, Allah makes some people succeed others in cultivating the earth, as in His saying: (And it is He who has made you successors on the earth), and (And [mention, O Muhammad], when your Lord said to the angels, "Indeed, I will make upon the earth a successor"), meaning a type [of creation] that succeeds those who came before it.

It is disliked to call a ruler "Allah's Caliph." Rather, one should say: "the Caliph," or "the Caliph of the Messenger of Allah, peace and blessings be upon him," or "Amir al-Mu'minin (Commander of the Faithful)." Abu Bakr and Umar, may Allah be pleased with them, both disapproved of being addressed as "O Caliph of Allah." Some allowed calling the Imam "Allah's Caliph" because he upholds His rights and due to His saying: (It is He who has made you successors on the earth). However, the majority of scholars forbade this and attributed the one who says it to immorality.