Section: The Innovations Introduced by the Jews and Christians in Their Religion

These proofs—and many more like them—make it clear that the Prophet himself, may Allah bless him and grant him peace, proclaimed that he is Allah’s Messenger to the Christians and to the rest of the People of the Book; that he summoned them, fought against them, and instructed that they be summoned and fought. This is not something his community later invented as a new practice, as the Christians did after the Messiah, peace be upon him. For Muslims do not allow anyone, after Muhammad—may Allah bless him and grant him peace—to alter any part of his Sacred Law: no one may pronounce lawful what he declared unlawful, or unlawful what he declared lawful; no one may impose as obligatory what he revoked, or revoke what he made obligatory. Rather, what is lawful for them is what Allah and His Messenger have declared lawful; what is unlawful is what Allah and His Messenger have declared unlawful; and religion itself is only what Allah and His Messenger have legislated.

This stands in stark contrast to the Christians, who after the Messiah fabricated innovations that he, peace be upon him, never prescribed and to which none of the Gospels or the earlier prophetic books give voice. Yet they claim that whatever their leading figures legislate as religion, the Messiah will endorse for them. It is over this very issue that the three communities—Muslims, Jews, and Christians—have disagreed, just as they have differed about the Messiah, peace be upon him, and about other matters.