The Exalted said:
“They have taken their rabbis and monks as lords apart from Allah—and also the Messiah, son of Mary—although they were commanded to worship but One God. There is no god but He; exalted is He above whatever they associate with Him.” (al-Tawbah 9:31)
Part of their associating others with Him was that their scholars made the unlawful lawful and they obeyed them, and they made the lawful unlawful and they obeyed them.
Allah, Most High, also said:
“Fight those from among the People of the Book who neither believe in Allah nor the Last Day, who do not forbid what Allah and His Messenger have forbidden, and who do not follow the religion of truth, until they pay the jizyah with their own hands in willing submission and feel themselves subdued.” (al-Tawbah 9:29)
Thus, alongside their failure to believe in Allah and the Last Day, He coupled their unbelief with the fact that they do not forbid what Allah and His Messenger have forbidden and do not adhere to the religion of truth.
The believers, however, held the Messenger—may Allah bless him and his family and grant them peace—to be truthful in everything he conveyed from Allah and about the Last Day. They believed in Allah and the Last Day and obeyed him in whatever he commanded and forbade, and in whatever he declared lawful and unlawful. They therefore prohibited what Allah and His Messenger have prohibited and embraced the religion of truth. For Allah sent the Messenger to command them to what is right and forbid them what is wrong, to make lawful for them what is wholesome and declare unlawful for them what is foul. He commanded them to every good, forbade them every evil, made lawful for them every pure thing, and made unlawful for them every impure thing.
The very word “Islam” encompasses both surrender and compliance, and it also carries the sense of exclusive devotion