The evidence of this is that God Himself commanded the...

The evidence of this is that God Himself commanded the believers to obey the Messenger and said: "O you who believe obey God and obey the Messenger and the people of authority from among you. If you dispute among yourselves about a matter return it to God and the Messenger if you believe in God and the Hereafter. That is best and most suitable for a final determination." The Holy Qur'an chapter 4 verse 59.

The Messenger had the right to establish for the Muslims after him a government he chooses for them. The Holy Qur'an gives him that right: "The Prophet has more authority over the believers than they have over themselves..." The Holy Qur'an chapter 33 verse 6. As he had this authority…