Restore The Islamic Caliphate
"It is permitted to have only one leader (of the Muslims) in the whole of the world."
"It is forbidden for Muslims to have in the whole world and at the same time two leaders whether in agreement or discord."
Prophethood will remain with you for as long as Allah wills it to remain, then Allah will raise it up wherever he wills to raise it up. Afterwards, there will be a Caliphate that follows the guidance of Prophethood remaining with you for as long as Allah wills it to remain. Then, He will raise it up whenever He wills to raise it up. Afterwards, there will be a reign of violently oppressive rule and it will remain with you for as long as Allah wills it to remain. Then, there will be a reign of tyrannical rule and it will remain for as long as Allah wills it to remain. Then, Allah will raise it up whenever He wills to raise it up. Then, there will be a Caliphate that follows the guidance of Prophethood.
— As-Silsilah As-Sahihah, vol. 1, no. 5
