Al-Shafi’i (may Allah have mercy on him) said: Allah made His Messenger (SAW) prevail over all religions by demonstrating to all who heard him that He was true, and whatever religion contradicted him was false. He said: He made him prevail by the fact that idolatry [shirk] encompasses two religions: the religion of the People of the Book and the religion of the illiterate [i.e. who have no books]. And the Messenger of Allah (SAW) conquered the illiterates until they professed Islam willingly or under compulsion, and He killed the People of the Book and took prisoners until some of them professed Islam and others of them gave jizya, being abased, and his authority came over them. This is how He prevailed over all religion. And Allah knows best.