Overall meaning :
The unbelievers from among the Jews and the Christians and the idolaters were not going to leave their religion until the clear sign and evidence from their Lord bearing witness to the truth came to them. Such clear evidence is the Messenger of Allah Muhammad, may Allah bless him and grant him peace, reciting to them the Qur’an that is written on pages which are purified from all falsehood, containing upright precepts and commandments.
The Jews and the Christians differed about Muhammad, may Allah bless him and grant him peace, only after Allah had sent him as a messenger, with the result that some of them believed him while others denied him! They were only commanded to worship Allah Alone with sincere dedication and purity of faith, abstaining from ascribing any partners to Him, and to perform the prescribed prayers and pay the prescribed charity (zakat). That is indeed the straight and just religion of Islam.