No one can be Khalifa unless the Muslims appoint him, and no one possesses the mandatory powers of the leadership of the State unless the contract with him has been concluded according tothe Shari’ah, like any contract in Islam.

The evidence is that the Khilafah is a contract upon satisfaction and consent, since its reality as a contract means it is not contracted except through two contracting parties, and, therefore, no one is the Khalifah unless he was appointed to it by those whose agreement completes the conclusion of the contract according to the Shari’ah. So if someone appoints himself Khalifah without the pledge from those whom the Khilafah is contracted through, then he would not be a Khalifah until his pledge occurs with choice and consent from those whom the conclusion of the contract takes place. So the fact that the Khilafah is a contract necessitates the presence of two contracting parties, with each of them having the necessary Shari’ah qualifications to be entrusted with the contract and conclude it.

If a conqueror came about and took the ruling by force he does not become a Khalifah by that, even if he announces himself as Khalifah of the Muslims, since the Khilafah was not contracted to him by the Muslims. If he took the pledge of allegiance from the people by force and compulsion, he does not become the Khalifah even if he was given the pledge, since the pledge given through compulsion and force is not considered, and so the Khilafah cannot be contracted by it. This is because a contract of choice and consent cannot be completed through compulsion and force, and so it is not contracted except through a pledge given with satisfaction and consent. However, if this conqueror managed to convince the people that it was in the benefit of the Muslims to give him the pledge, and that the implementation of the Shari’ah would be complete through giving the pledge to him – and so the people became convinced and satisfied with that and gave him the pledge of allegiance on that basis with their own choice, then he would become the Khalifah from the moment that he was given that pledge by the people freely even though he took the authority through force and power. Therefore, the condition is the contracting of the pledge, and this is only reached through consent and choice, irrespective of whether the one who reached it was the ruler and leader, or wasn’t.