about Christ and Moses—and Muhammad as well, may Allah’s blessings and peace be upon them all—in the reports found, for example, in the Sīrah of Ibn Isḥāq, in the Sunan collections, and in the Musnad compilations traced back to the Prophet ﷺ. Of every one of these books there are numerous copies spread across the world; consequently, no one could alter an entire lengthy section. Still, within the Sīrah certain passages are in error, and some of the ḥadiths found in the Sunan were mistaken from the start. The fact that many copies later became widespread does not prevent error having existed in the original.

Exactly the same holds for the works of Qurʾānic exegesis, jurisprudence, and the more specialized treatises: each of them exists in many copies worldwide, so that it is impossible to tamper with a long chapter, yet they, too, contain ḥadiths that were already unsound in the source.

The Gospels now in the hands of the Christians are comparable. That is why they were instructed to judge by what those Gospels contain: within them are Allah’s rulings, and the wording of the great majority of those rulings has not been changed. What was changed is confined to some phrasing in the narrative portions and to certain meanings in the commands—just as we are enjoined to act upon the well-known legal ḥadiths traced back to the Prophet ﷺ. The scholars devoted more care to preserving those than they did to purely narrative reports, such as ḥadiths on asceticism, stories, merits, and the like, for the nations’ need to know commands and prohibitions is greater than their need for the detailed narratives in which a general belief suffices.

As for command and prohibition themselves, they must be known in detail: one cannot carry out what is enjoined except in a specific manner, and that which is forbidden—and must therefore be avoided—must be clearly distinguished from what is not, just as the Exalted has said: