According to Imam Khomeini, the path of the Prophet (PBUH) constitute a proof of the necessity for establishing government. First, he himself established a government, as history testifies.
He engaged in the implementation of laws, the establishment of the ordinances of Islam, and the administration of society.
He sent out governors to different regions; both sat in judgment himself and also appointed judges; dispatched emissaries to foreign states, tribal chieftains, and kings; concluded treaties and pacts; and took command in battle. In short, he fulfilled all the functions of government. Second, he designated a ruler to succeed him, in accordance with divine command.